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38 results on '"Debbe RR"'

1. Collision energy dependence of moments of net-kaon multiplicity distributions at RHIC

Author

Adamczyk, L, Adams, JR, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Barish, K, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, and Harlenderova, A

Subjects
nucl-ex, hep-ex, hep-ph, nucl-th, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

Fluctuations of conserved quantities such as baryon number, charge, and strangeness are sensitive to the correlation length of the hot and dense matter created in relativistic heavy-ion collisions and can be used to search for the QCD critical point. We report the first measurements of the moments of net-kaon multiplicity distributions in Au+Au collisions at sNN=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV. The collision centrality and energy dependence of the mean (M), variance (σ2), skewness (S), and kurtosis (κ) for net-kaon multiplicity distributions as well as the ratio σ2/M and the products Sσ and κσ2 are presented. Comparisons are made with Poisson and negative binomial baseline calculations as well as with UrQMD, a transport model (UrQMD) that does not include effects from the QCD critical point. Within current uncertainties, the net-kaon cumulant ratios appear to be monotonic as a function of collision energy.

Published
2018

2. Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at sNN=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV

Author

Adamczyk, L, Adams, JR, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Barish, K, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, and Harlenderova, A

Subjects
Affordable and Clean Energy, STAR Collaboration, nucl-ex, hep-ex, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

We report measurements of the nuclear modification factor R_{CP} for charged hadrons as well as identified π^{+(-)}, K^{+(-)}, and p(p[over ¯]) for Au+Au collision energies of sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-p_{T} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP} at high p_{T} does depend on the collision energy, neither the proton nor the antiproton R_{CP} at high p_{T} exhibit net suppression at any energy. A study of how the binary collision-scaled high-p_{T} yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.

Published
2018

3. Energy dependence of J/ψ production in Au + Au collisions at sNN=39,62.4 and 200GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, Harris, JW, and He, L

Subjects
hep-ex, nucl-ex, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (|y|

Published
2017

4. Energy dependence of J/ψ production in Au+Au collisions at sNN=39,62.4 and 200GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, Harris, JW, and He, L

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Affordable and Clean Energy, hep-ex, nucl-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract

The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (|y|

Published
2017

5. Direct virtual photon production in Au+Au collisions at sNN=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, Harris, JW, and He, L

Subjects
nucl-ex, hep-ex, hep-ph, nucl-th, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

We report the direct virtual photon invariant yields in the transverse momentum ranges 16 GeV/c the production follows TAA scaling. Model calculations with contributions from thermal radiation and initial hard parton scattering are consistent within uncertainties with the direct virtual photon invariant yield.

Published
2017

6. Measurement of the cross section and longitudinal double-spin asymmetry for dijet production in polarized pp collisions at s=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Barish, K, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, and Harris, JW

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, hep-ex, nucl-ex
Abstract

We report the first measurement of the longitudinal double-spin asymmetry ALL for midrapidity dijet production in polarized pp collisions at a center-of-mass energy of s=200 GeV. The dijet cross section was measured and is shown to be consistent with next-to-leading order (NLO) perturbative QCD predictions. ALL results are presented for two distinct topologies, defined by the jet pseudorapidities, and are compared to predictions from several recent NLO global analyses. The measured asymmetries, the first such correlation measurements, support those analyses that find positive gluon polarization at the level of roughly 0.2 over the region of Bjorken-x>0.05.

Published
2017

7. Measurement of the cross section and longitudinal double-spin asymmetry for dijet production in polarized pp collisions at s =200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Barish, K, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Calderón De La Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, and Harris, JW

Subjects
hep-ex, nucl-ex
Abstract

We report the first measurement of the longitudinal double-spin asymmetry ALL for midrapidity dijet production in polarized pp collisions at a center-of-mass energy of s=200 GeV. The dijet cross section was measured and is shown to be consistent with next-to-leading order (NLO) perturbative QCD predictions. ALL results are presented for two distinct topologies, defined by the jet pseudorapidities, and are compared to predictions from several recent NLO global analyses. The measured asymmetries, the first such correlation measurements, support those analyses that find positive gluon polarization at the level of roughly 0.2 over the region of Bjorken-x>0.05.

Published
2017

8. Elliptic flow of electrons from heavy-flavor hadron decays in Au + Au collisions at √sNN =200, 62.4, and 39 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Calderón De La Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, Harris, JW, He, L, and Heppelmann, S

Subjects
hep-ex, nucl-ex
Abstract

We present measurements of elliptic flow (v2) of electrons from the decays of heavy-flavor hadrons (eHF) by the STAR experiment. For Au+Au collisions at sNN=200 GeV we report v2, for transverse momentum (pT) between 0.2 and 7 GeV/c, using three methods: the event plane method (v2{EP}), two-particle correlations (v2{2}), and four-particle correlations (v2{4}). For Au+Au collisions at sNN=62.4 and 39 GeV we report v2{2} for pT

Published
2017

9. Elliptic flow of electrons from heavy-flavor hadron decays in Au + Au collisions at sNN=200, 62.4, and 39 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, Harris, JW, He, L, and Heppelmann, S

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, nucl-ex, Nuclear and plasma physics
Abstract

We present measurements of elliptic flow (v2) of electrons from the decays of heavy-flavor hadrons (eHF) by the STAR experiment. For Au+Au collisions at sNN=200 GeV we report v2, for transverse momentum (pT) between 0.2 and 7 GeV/c, using three methods: the event plane method (v2{EP}), two-particle correlations (v2{2}), and four-particle correlations (v2{4}). For Au+Au collisions at sNN=62.4 and 39 GeV we report v2{2} for pT

Published
2017

10. Coherent diffractive photoproduction of $ρ^{0}$ mesons on gold nuclei at RHIC

Author

Collaboration, STAR, Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Sánchez, M Calderón de la Barca, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, Silva, LC De, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, and Harris, JW

Subjects
nucl-ex, hep-ex
Abstract

The STAR Collaboration reports on the photoproduction of $\pi^+\pi^-$ pairsin gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair.These pion pairs are produced when a nearly-real photon emitted by one ionscatters from the other ion. We fit the $\pi^+\pi^-$ invariant mass spectrum with a combination of $\rho$and $\omega$ resonances and a direct $\pi^+\pi^-$ continuum. This is the firstobservation of the $\omega$ in ultra-peripheral collisions, and the firstmeasurement of $\rho-\omega$ interference at energies where photoproduction isdominated by Pomeron exchange. The $\omega$ amplitude is consistent with themeasured $\gamma p\rightarrow \omega p$ cross section, a classical Glaubercalculation and the $\omega\rightarrow\pi^+\pi^-$ branching ratio. The $\omega$phase angle is similar to that observed at much lower energies, showing thatthe $\rho-\omega$ phase difference does not depend significantly on photonenergy. The $\rho^0$ differential cross section $d\sigma/dt$ exhibits a cleardiffraction pattern, compatible with scattering from a gold nucleus, with 2minima visible. The positions of the diffractive minima agree better with thepredictions of a quantum Glauber calculation that does not include nuclearshadowing than with a calculation that does include shadowing.

Published
2017

11. ϒ production in U + U collisions at sNN =193 GeV measured with the STAR experiment

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Calderón De La Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chatterjee, A, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, HZ, and Huang, B

Subjects
nucl-ex, hep-ex
Abstract

We present a measurement of the inclusive production of ϒ mesons in U+U collisions at sNN=193 GeV at midrapidity (|y|

Published
2016

12. Υ production in U + U collisions at sNN=193 GeV measured with the STAR experiment

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chatterjee, A, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, HZ, and Huang, B

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, nucl-ex, hep-ex, Nuclear and plasma physics
Abstract

We present a measurement of the inclusive production of ϒ mesons in U+U collisions at sNN=193 GeV at midrapidity (|y|

Published
2016

13. Jet-like correlations with direct-photon and neutral-pion triggers at sNN=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Anderson, DM, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, T, Huang, B, Huang, X, and Huang, HZ

Subjects
nucl-ex, hep-ex, hep-ph, nucl-th, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

Azimuthal correlations of charged hadrons with direct-photon (γdir) and neutral-pion (π0) trigger particles are analyzed in central Au+Au and minimum-bias p+p collisions at sNN=200 GeV in the STAR experiment. The charged-hadron per-trigger yields at mid-rapidity from central Au+Au collisions are compared with p+p collisions to quantify the suppression in Au+Au collisions. The suppression of the away-side associated-particle yields per γdir trigger is independent of the transverse momentum of the trigger particle (pTtrig), whereas the suppression is smaller at low transverse momentum of the associated charged hadrons (pTassoc). Within uncertainty, similar levels of suppression are observed for γdir and π0 triggers as a function of zT (≡pTassoc/pTtrig). The results are compared with energy-loss-inspired theoretical model predictions. Our studies support previous conclusions that the lost energy reappears predominantly at low transverse momentum, regardless of the trigger energy.

Published
2016

14. Measurement of the Transverse Single-Spin Asymmetry in p↑+p→W±/Z0 at RHIC

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, X, Huang, HZ, Huang, B, Huang, T, and Huck, P

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Quantum Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, STAR Collaboration, nucl-ex, hep-ex, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at sqrt[s]=500  GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse-momentum-dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the nonuniversality of the Sivers function, fundamental to our understanding of QCD.

Published
2016

15. Centrality and Transverse Momentum Dependence of Elliptic Flow of Multistrange Hadrons and ϕ Meson in Au+Au Collisions at sNN=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Bairathi, V, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, X, Huang, B, Huang, HZ, Huck, P, Humanic, TJ, Igo, G, and Jacobs, WW

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, STAR Collaboration, nucl-ex, hep-ex, hep-ph, nucl-th, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

We present high precision measurements of elliptic flow near midrapidity (|y|

Published
2016

16. Centrality and Transverse Momentum Dependence of Elliptic Flow of Multistrange Hadrons and ϕ Meson in Au+Au Collisions at √[sNN]=200  GeV.

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Bairathi, V, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, X, Huang, B, Huang, HZ, Huck, P, Humanic, TJ, Igo, G, and Jacobs, WW

Subjects
STAR Collaboration, nucl-ex, hep-ex, hep-ph, nucl-th, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract

We present high precision measurements of elliptic flow near midrapidity (|y|

Published
2016

17. Measurement of elliptic flow of light nuclei at $\sqrt{s_{NN}}$ = 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV at RHIC

Author

Collaboration, STAR, Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Sánchez, M Calderón de la Barca, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, Silva, LC De, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Ruzza, B di, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, T, Huang, HZ, Huang, X, and Huang, B

Subjects
nucl-ex, hep-ex, hep-ph
Abstract

We present measurements of 2$^{nd}$ order azimuthal anisotropy ($v_{2}$) atmid-rapidity $(|y|

Published
2016

18. Observation of Transverse Spin-Dependent Azimuthal Correlations of Charged Pion Pairs in p↑+p at s=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, B, Huang, X, Huang, HZ, Huck, P, Humanic, TJ, and Igo, G

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Quantum Physics, Physical Sciences, STAR Collaboration, hep-ex, nucl-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p^{↑}+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities η>0.5, and for pair masses around the mass of the ρ meson. This is the first direct transversity measurement in p+p collisions.

Published
2015

19. Energy dependence of acceptance-corrected dielectron excess mass spectrum at mid-rapidity in Au+Au collisions at √sNN=19.6 and 200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calder'on de la Barca S'anchez, M, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Codrington, MJM, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, HZ, Huang, X, Huang, B, Huck, P, Humanic, TJ, and Igo, G

Subjects
hep-ex, nucl-ex, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity |yee|

Published
2015

20. Measurement of interaction between antiprotons

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Bairathi, V, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Sanchez, M Calderon de la Barca, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, B, Huang, HZ, Huang, X, Huck, P, and Humanic, TJ

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, STAR Collaboration, nucl-ex, hep-ex, nucl-th, General Science & Technology
Abstract

One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force that has since been acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, little is known directly about the nuclear force between antinucleons. Here, we study antiproton pair correlations among data collected by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC), where gold ions are collided with a centre-of-mass energy of 200 gigaelectronvolts per nucleon pair. Antiprotons are abundantly produced in such collisions, thus making it feasible to study details of the antiproton-antiproton interaction. By applying a technique similar to Hanbury Brown and Twiss intensity interferometry, we show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: the scattering length and the effective range of the interaction. Our measured parameters are consistent within errors with the corresponding values for proton-proton interactions. Our results provide direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, and so are fundamental to understanding the structure of more-complex antinuclei and their properties.

Published
2015

21. Energy dependence of acceptance-corrected dielectron excess mass spectrum at mid-rapidity in Au+Au collisions at sNN=19.6 and 200 GeV

Author

Collaboration, STAR, Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, de la Barca S'anchez, M Calder'on, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Codrington, MJM, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, HZ, Huang, X, Huang, B, Huck, P, and Humanic, TJ

Subjects
hep-ex, nucl-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract

The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity |yee|

Published
2015

22. Precision Measurement of the Longitudinal Double-Spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at s=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Contin, G, Cramer, JG, Crawford, HJ, Cudd, AB, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi de Souza, R, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, and Gupta, A

Subjects
STAR Collaboration, hep-ex, nucl-ex, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

We report a new measurement of the midrapidity inclusive jet longitudinal double-spin asymmetry, A_{LL}, in polarized pp collisions at center-of-mass energy sqrt[s]=200  GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep-inelastic scattering (DIS), semi-inclusive DIS, and RHIC pp data. The measured asymmetries provide evidence at the 3σ level for positive gluon polarization in the Bjorken-x region x>0.05.

Published
2015

23. Measurements of dielectron production in Au + Au collisions at sNN =200 GeV from the STAR experiment

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón De La Barca Sánchez, M, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, B, Huang, X, Huang, HZ, Huck, P, Humanic, TJ, and Igo, G

Subjects
hep-ex, nucl-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

We report on measurements of dielectron (e+e-) production in Au+Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at BNL Relativistic Heavy Ion Collider. Systematic measurements of the dielectron yield as a function of transverse momentum (pT) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region (Mee

Published
2015

24. Measurements of dielectron production in Au + Au collisions at sNN=200 GeV from the STAR experiment

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, B, Huang, X, Huang, HZ, Huck, P, Humanic, TJ, and Igo, G

Subjects
hep-ex, nucl-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract

We report on measurements of dielectron (e+e-) production in Au+Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at BNL Relativistic Heavy Ion Collider. Systematic measurements of the dielectron yield as a function of transverse momentum (pT) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region (Mee

Published
2015

25. Charged-to-neutral correlation at forward rapidity in Au + Au collisions at sNN =200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, De La Barca Sánchez, MC, Campbell, JM, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Contin, G, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi De Souza, R, Di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, and Haag, B

Subjects
nucl-ex, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

Event-by-event fluctuations of the multiplicities of inclusive charged particles and photons at forward rapidity in Au+Au collisions at sNN=200 GeV have been studied. The dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidence of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as base lines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A nonzero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation owing to particle decay. Results are compared to the expectations based on the generic production mechanism of pions owing to isospin symmetry, for which no significant (

Published
2015

26. The $φ(1020)\rightarrow e^{+}e^{-}$ meson decay measured with the STAR experiment in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV

Author

Collaboration, STAR, Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Sánchez, M Calderón de la Barca, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, Silva, LC De, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Ruzza, B di, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, X, Huang, HZ, Huang, T, and Huang, B

Subjects
hep-ex, nucl-ex
Abstract

We report the measurement of the leptonic ($e^{+}e^{-}$) decay channel of the$\phi$(1020) meson in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV by theSTAR experiment. The transverse momentum ($p_{\rm T}$) spectrum is measured for0.1 $\le p_{\rm T} \le 2.5$ GeV/$c$ at mid-rapidity ($|y|\le1$). We obtain the$p_{\rm T}$-integrated $\phi$(1020) mass $M_{\phi}=1017.7\pm0.8 (\rm {stat.})\pm0.9 (\rm {sys.})$ MeV/$c^{2}$ and width $\Gamma_{\phi} = 8.0\pm 2.5(\rm{stat.}) \pm 2.3(\rm {sys.}) \textrm{MeV/}c^{2}$, which are within1.5\,$\sigma$ and 1.1\,$\sigma$ of the vacuum values, respectively. Nosignificant difference is observed in the measured $p_{\rm T}$ spectrum,$dN/dy$, or $\left$ of the $\phi$(1020) meson between the$e^{+}e^{-}$ and hadronic ($K^{+}K^{-}$) decay channels as measured by the sameexperiment. The experimental results are compared to a theoretical modelincluding medium-modified $\phi$(1020).

Published
2015

27. Charged-to-neutral correlation at forward rapidity in Au + Au collisions at sNN=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Campbell, JM, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Contin, G, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Leyva, A Davila, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, de Souza, R Derradi, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, and Haag, B

Subjects
nucl-ex, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract

Event-by-event fluctuations of the multiplicities of inclusive charged particles and photons at forward rapidity in Au+Au collisions at sNN=200 GeV have been studied. The dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidence of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as base lines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A nonzero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation owing to particle decay. Results are compared to the expectations based on the generic production mechanism of pions owing to isospin symmetry, for which no significant (

Published
2015

28. Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC.

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Balewski, J, Banerjee, A, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Contin, G, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi de Souza, R, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, and Gupta, A

Subjects
(STAR Collaboration), Clinical Research, nucl-ex, hep-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract

We report measurements of single- and double-spin asymmetries for W^{±} and Z/γ^{*} boson production in longitudinally polarized p+p collisions at sqrt[s]=510  GeV by the STAR experiment at RHIC. The asymmetries for W^{±} were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton's polarized quark distributions at the scale of the W mass. The results are compared to theoretical predictions, constrained by polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range 0.05

Published
2014

29. Dielectron Mass Spectra from Au+Au Collisions at sNN=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Barnovska, Z, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi de Souza, R, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Grosnick, D, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Haag, B, Hajkova, O, and Hamed, A

Subjects
STAR Collaboration, hep-ex, nucl-ex, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

We report the STAR measurements of dielectron (e(+)e(-)) production at midrapidity (|y(ee)|

Published
2014

30. Dielectron mass spectra from Au+Au collisions at √[s(NN)]=200  GeV.

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Barnovska, Z, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi de Souza, R, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Grosnick, D, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Haag, B, Hajkova, O, and Hamed, A

Subjects
STAR Collaboration, hep-ex, nucl-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract

We report the STAR measurements of dielectron (e(+)e(-)) production at midrapidity (|y(ee)|

Published
2014

31. Beam-Energy Dependence of the Directed Flow of Protons, Antiprotons, and Pions in Au+Au Collisions

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Banerjee, A, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Contin, G, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi de Souza, R, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, and Guryn, W

Subjects
(STAR Collaboration), nucl-ex, hep-ex, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y=0) are reported in sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton dv1/dy|y=0 changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.

Published
2014

32. Energy Dependence of Moments of Net-Proton Multiplicity Distributions at RHIC

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Balewski, J, Banerjee, A, Barnovska, Z, Beavis, DR, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Corliss, R, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi de Souza, R, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Fatemi, R, Fazio, S, Fedorisin, J, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, Grosnick, D, Guo, Y, Gupta, A, Gupta, S, Guryn, W, and Haag, B

Subjects
STAR Collaboration, nucl-ex, hep-ex, hep-lat, hep-ph, nucl-th, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

We report the beam energy (sqrt[sNN]=7.7-200  GeV) and collision centrality dependence of the mean (M), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y|

Published
2014

33. Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at s = 200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Balewski, J, Banerjee, A, Barber, B, Barnovska, Z, Beavis, DR, Bellwied, R, Betancourt, MJ, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Bridgeman, A, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, Calderón De La Barca Sánchez, M, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Corliss, R, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Davila Leyva, A, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Derradi De Souza, R, Dhamija, S, Di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Dion, A, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Fatemi, R, Fazio, S, Fedorisin, J, Fersch, RG, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, and Grosnick, D

Subjects
nucl-ex, hep-ex, Nuclear & Particles Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8

Published
2014

34. Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at s=200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Alford, J, Anson, CD, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Balewski, J, Banerjee, A, Barber, B, Barnovska, Z, Beavis, DR, Bellwied, R, Betancourt, MJ, Bhasin, A, Bhati, AK, Bhattarai, P, Bichsel, H, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Borowski, W, Bouchet, J, Brandin, AV, Bridgeman, A, Brovko, SG, Bültmann, S, Bunzarov, I, Burton, TP, Butterworth, J, Caines, H, de la Barca Sánchez, M Calderón, Cebra, D, Cendejas, R, Cervantes, MC, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, HF, Chen, JH, Chen, L, Cheng, J, Cherney, M, Chikanian, A, Christie, W, Chwastowski, J, Codrington, MJM, Corliss, R, Cramer, JG, Crawford, HJ, Cui, X, Das, S, Leyva, A Davila, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, de Souza, R Derradi, Dhamija, S, di Ruzza, B, Didenko, L, Dilks, C, Ding, F, Dion, A, Djawotho, P, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Engle, KS, Eppley, G, Eun, L, Evdokimov, O, Fatemi, R, Fazio, S, Fedorisin, J, Fersch, RG, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Gagliardi, CA, Gangadharan, DR, Garand, D, Geurts, F, Gibson, A, Girard, M, Gliske, S, and Grosnick, D

Subjects
nucl-ex, hep-ex, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract

The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8

Published
2014

35. Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at sNN =7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV

Author

Adamczyk, L, Adams, JR, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Barish, K, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, De La Barca Sánchez, MC, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, AI, and Hamed, A

Subjects
hep-ex, High Energy Physics::Experiment, Nuclear Experiment, nucl-ex
Abstract

© 2018 American Physical Society. We report measurements of the nuclear modification factor RCP for charged hadrons as well as identified π+(-), K+(-), and p(p) for Au+Au collision energies of sNN=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-pT net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton RCP at high pT does depend on the collision energy, neither the proton nor the antiproton RCP at high pT exhibit net suppression at any energy. A study of how the binary collision-scaled high-pT yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.

Published
2018

36. Coherent diffractive photoproduction of $ρ^{0}$ mesons on gold nuclei at RHIC

Author

Collaboration, STAR, Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Ajitanand, NN, Alekseev, I, Anderson, DM, Aoyama, R, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Behera, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Brown, D, Bunzarov, I, Butterworth, J, Caines, H, Sánchez, MCDLB, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chankova-Bunzarova, N, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, Silva, LCD, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Elsey, N, Engelage, J, Eppley, G, Esha, R, Esumi, S, Evdokimov, O, Ewigleben, J, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Federicova, P, Fedorisin, J, Feng, Z, Filip, P, Finch, E, Fisyak, Y, Flores, CE, Fujita, J, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Harlenderova, A, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, B, Huang, T, Huang, HZ, Huang, X, Humanic, TJ, Huo, P, Igo, G, Jacobs, WW, Jentsch, A, Jia, J, Jiang, K, Jowzaee, S, Judd, EG, Kabana, S, Kalinkin, D, Kang, K, Kauder, K, Ke, HW, Keane, D, Kechechyan, A, Khan, Z, Kikoła, DP, Kisel, I, Kisiel, A, Klein, SR, Kochenda, L, Kocmanek, M, Kollegger, T, Kosarzewski, LK, Kraishan, AF, Kravtsov, P, Krueger, K, Kulathunga, N, Kumar, L, Kvapil, J, Kwasizur, JH, Lacey, R, Landgraf, JM, Landry, KD, Lauret, J, Lebedev, A, Lednicky, R, Lee, JH, Li, W, Li, X, Li, C, Li, Y, Lidrych, J, Lin, T, Lisa, MA, Liu, Y, Liu, F, Liu, H, Liu, P, Ljubicic, T, Llope, WJ, Lomnitz, M, Longacre, RS, Luo, S, Luo, X, Ma, GL, Ma, YG, Ma, L, Ma, R, Magdy, N, Majka, R, Mallick, D, Margetis, S, Markert, C, Matis, HS, Meehan, K, Mei, JC, Miller, ZW, Minaev, NG, Mioduszewski, S, Mishra, D, Mizuno, S, Mohanty, B, Mondal, MM, Morozov, DA, Mustafa, MK, Nasim, M, Nayak, TK, Nelson, JM, Nie, M, Nigmatkulov, G, Niida, T, Nogach, LV, Nonaka, T, Nurushev, SB, Odyniec, G, Ogawa, A, Oh, K, Okorokov, VA, Jr, DO, Page, BS, Pak, R, Pandit, Y, Panebratsev, Y, Pawlik, B, Pei, H, Perkins, C, Pile, P, Pluta, J, Poniatowska, K, Porter, J, Posik, M, Poskanzer, AM, Pruthi, NK, Przybycien, M, Putschke, J, Qiu, H, Quintero, A, Ramachandran, S, Ray, RL, Reed, R, Rehbein, MJ, Ritter, HG, Roberts, JB, Rogachevskiy, OV, Romero, JL, Roth, JD, Ruan, L, Rusnak, J, Rusnakova, O, Sahoo, NR, Sahu, PK, Salur, S, Sandweiss, J, Saur, M, Schambach, J, Schmah, AM, Schmidke, WB, Schmitz, N, Schweid, BR, Seger, J, Sergeeva, M, Seyboth, P, Shah, N, Shahaliev, E, Shanmuganathan, PV, Shao, M, Sharma, A, Sharma, MK, Shen, WQ, Shi, Z, Shi, SS, Shou, QY, Sichtermann, EP, Sikora, R, Simko, M, Singha, S, Skoby, MJ, Smirnov, N, Smirnov, D, Solyst, W, Song, L, Sorensen, P, Spinka, HM, Srivastava, B, Stanislaus, TDS, Strikhanov, M, Stringfellow, B, Sugiura, T, Sumbera, M, Summa, B, Sun, Y, Sun, XM, Sun, X, Surrow, B, Svirida, DN, Tang, AH, Tang, Z, Taranenko, A, Tarnowsky, T, Tawfik, A, Thäder, J, Thomas, JH, Timmins, AR, Tlusty, D, Todoroki, T, Tokarev, M, Trentalange, S, Tribble, RE, Tribedy, P, Tripathy, SK, Trzeciak, BA, Tsai, OD, Ullrich, T, Underwood, DG, Upsal, I, Buren, GV, Nieuwenhuizen, GV, Vasiliev, AN, Videbæk, F, Vokal, S, Voloshin, SA, Vossen, A, Wang, G, Wang, Y, Wang, F, Webb, JC, Webb, G, Wen, L, Westfall, GD, Wieman, H, Wissink, SW, Witt, R, Wu, Y, Xiao, ZG, Xie, W, Xie, G, Xu, J, Xu, N, Xu, QH, Xu, YF, Xu, Z, Yang, Y, Yang, Q, Yang, C, Yang, S, Ye, Z, Yi, L, Yip, K, Yoo, I-K, Yu, N, Zbroszczyk, H, Zha, W, Zhang, Z, Zhang, XP, Zhang, JB, Zhang, S, Zhang, J, Zhang, Y, Zhao, J, Zhong, C, Zhou, L, Zhou, C, Zhu, X, Zhu, Z, and Zyzak, M

Subjects
hep-ex, Nuclear Experiment, nucl-ex
Abstract

The STAR Collaboration reports on the photoproduction of $\pi^+\pi^-$ pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly-real photon emitted by one ion scatters from the other ion. We fit the $\pi^+\pi^-$ invariant mass spectrum with a combination of $\rho$ and $\omega$ resonances and a direct $\pi^+\pi^-$ continuum. This is the first observation of the $\omega$ in ultra-peripheral collisions, and the first measurement of $\rho-\omega$ interference at energies where photoproduction is dominated by Pomeron exchange. The $\omega$ amplitude is consistent with the measured $\gamma p\rightarrow \omega p$ cross section, a classical Glauber calculation and the $\omega\rightarrow\pi^+\pi^-$ branching ratio. The $\omega$ phase angle is similar to that observed at much lower energies, showing that the $\rho-\omega$ phase difference does not depend significantly on photon energy. The $\rho^0$ differential cross section $d\sigma/dt$ exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with 2 minima visible. The positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.

Published
2018

37. Centrality and Transverse Momentum Dependence of Elliptic Flow of Multistrange Hadrons and φ Meson in Au+Au Collisions at sNN =200 GeV

Author

Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Averichev, GS, Bairathi, V, Banerjee, A, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Calderón de la Barca Sánchez, M, Campbell, JM, Cebra, D, Cervantes, MC, Chakaberia, I, Chaloupka, P, Chang, Z, Chattopadhyay, S, Chen, JH, Chen, X, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, De Silva, LC, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, di Ruzza, B, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, S, Gupta, A, Guryn, W, Hamad, A, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Hofman, DJ, Horvat, S, Huang, X, Huang, B, Huang, HZ, Huck, P, Humanic, TJ, Igo, G, and Jacobs, WW

Subjects
STAR Collaboration, General Physics, Engineering, nucl-th, hep-ex, Physical Sciences, High Energy Physics::Phenomenology, Nuclear Theory, hep-ph, High Energy Physics::Experiment, nucl-ex, Nuclear Experiment, Mathematical Sciences
Abstract

© 2016 American Physical Society. We present high precision measurements of elliptic flow near midrapidity (|y

Published
2016

38. The $\phi (1020)\rightarrow e^{+}e^{-}$ meson decay measured with the STAR experiment in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV

Author

Collaboration, STAR, Adamczyk, L, Adkins, JK, Agakishiev, G, Aggarwal, MM, Ahammed, Z, Alekseev, I, Aparin, A, Arkhipkin, D, Aschenauer, EC, Ashraf, MU, Attri, A, Averichev, GS, Bai, X, Bairathi, V, Bellwied, R, Bhasin, A, Bhati, AK, Bhattarai, P, Bielcik, J, Bielcikova, J, Bland, LC, Bordyuzhin, IG, Bouchet, J, Brandenburg, JD, Brandin, AV, Bunzarov, I, Butterworth, J, Caines, H, Sánchez, MCDLB, Campbell, JM, Cebra, D, Chakaberia, I, Chaloupka, P, Chang, Z, Chatterjee, A, Chattopadhyay, S, Chen, X, Chen, JH, Cheng, J, Cherney, M, Christie, W, Contin, G, Crawford, HJ, Das, S, Silva, LCD, Debbe, RR, Dedovich, TG, Deng, J, Derevschikov, AA, Ruzza, BD, Didenko, L, Dilks, C, Dong, X, Drachenberg, JL, Draper, JE, Du, CM, Dunkelberger, LE, Dunlop, JC, Efimov, LG, Engelage, J, Eppley, G, Esha, R, Evdokimov, O, Eyser, O, Fatemi, R, Fazio, S, Federic, P, Fedorisin, J, Feng, Z, Filip, P, Fisyak, Y, Flores, CE, Fulek, L, Gagliardi, CA, Garand, D, Geurts, F, Gibson, A, Girard, M, Greiner, L, Grosnick, D, Gunarathne, DS, Guo, Y, Gupta, A, Gupta, S, Guryn, W, Hamad, AI, Hamed, A, Haque, R, Harris, JW, He, L, Heppelmann, S, Hirsch, A, Hoffmann, GW, Horvat, S, Huang, X, Huang, HZ, Huang, T, Huang, B, Huck, P, Humanic, TJ, Igo, G, Jacobs, WW, Jang, H, Jentsch, A, Jia, J, Jiang, K, Judd, EG, Kabana, S, Kalinkin, D, Kang, K, Kauder, K, Ke, HW, Keane, D, Kechechyan, A, Khan, ZH, Kikoła, DP, Kisel, I, Kisiel, A, Kochenda, L, Koetke, DD, Kosarzewski, LK, Kraishan, AF, Kravtsov, P, Krueger, K, Kumar, L, Lamont, MAC, Landgraf, JM, Landry, KD, Lauret, J, Lebedev, A, Lednicky, R, Lee, JH, Li, C, Li, Y, Li, X, Li, W, Lin, T, Lisa, MA, Liu, F, Ljubicic, T, Llope, WJ, Lomnitz, M, Longacre, RS, Luo, X, Ma, R, Ma, GL, Ma, L, Ma, YG, Magdy, N, Majka, R, Manion, A, Margetis, S, Markert, C, Matis, HS, McDonald, D, McKinzie, S, Meehan, K, Mei, JC, Minaev, NG, Mioduszewski, S, Mishra, D, Mohanty, B, Mondal, MM, Morozov, DA, Mustafa, MK, Nandi, BK, Nasim, M, Nayak, TK, Nigmatkulov, G, Niida, T, Nogach, LV, Noh, SY, Novak, J, Nurushev, SB, Odyniec, G, Ogawa, A, Oh, K, Okorokov, VA, Jr, DO, Page, BS, Pak, R, Pan, YX, Pandit, Y, Panebratsev, Y, Pawlik, B, Pei, H, Perkins, C, Pile, P, Pluta, J, Poniatowska, K, Porter, J, Posik, M, Poskanzer, AM, Pruthi, NK, Putschke, J, Qiu, H, Quintero, A, Ramachandran, S, Ray, RL, Ritter, HG, Roberts, JB, Rogachevskiy, OV, Romero, JL, Ruan, L, Rusnak, J, Rusnakova, O, Sahoo, NR, Sahu, PK, Sakrejda, I, Salur, S, Sandweiss, J, Sarkar, A, Schambach, J, Scharenberg, RP, Schmah, AM, Schmidke, WB, Schmitz, N, Seger, J, Seyboth, P, Shah, N, Shahaliev, E, Shanmuganathan, PV, Shao, M, Sharma, B, Sharma, MK, Sharma, A, Shen, WQ, Shi, Z, Shi, SS, Shou, QY, Sichtermann, EP, Sikora, R, Simko, M, Singha, S, Skoby, MJ, Smirnov, D, Smirnov, N, Solyst, W, Song, L, Sorensen, P, Spinka, HM, Srivastava, B, Stanislaus, TDS, Stepanov, M, Stock, R, Strikhanov, M, Stringfellow, B, Sumbera, M, Summa, B, Sun, Y, Sun, XM, Sun, Z, Surrow, B, Svirida, DN, Tang, Z, Tang, AH, Tarnowsky, T, Tawfik, A, Thäder, J, Thomas, JH, Timmins, AR, Tlusty, D, Todoroki, T, Tokarev, M, Trentalange, S, Tribble, RE, Tribedy, P, Tripathy, SK, Tsai, OD, Ullrich, T, Underwood, DG, Upsal, I, Buren, GV, Nieuwenhuizen, GV, Vandenbroucke, M, Varma, R, Vasiliev, AN, Vertesi, R, Videbæk, F, Vokal, S, Voloshin, SA, Vossen, A, Wada, M, Wang, Y, Wang, F, Wang, G, Wang, JS, Wang, H, Webb, G, Webb, JC, Wen, L, Westfall, GD, Wieman, H, Wissink, SW, Witt, R, Wu, Y, Xiao, ZG, Xie, W, Xie, G, Xin, K, Xu, YF, Xu, H, Xu, Z, Xu, J, Xu, N, Xu, QH, Yang, Y, Yang, C, Yang, Q, Yang, S, Ye, Z, Yepes, P, Yi, L, Yip, K, Yoo, I-K, Yu, N, Zbroszczyk, H, Zha, W, Zhang, S, Zhang, J, Zhang, JB, Zhang, XP, Zhang, Y, Zhang, Z, Zhao, J, Zhong, C, Zhou, L, Zhu, X, Zoulkarneeva, Y, and Zyzak, M

Subjects
hep-ex, High Energy Physics::Experiment, nucl-ex, Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report the measurement of the leptonic ($e^{+}e^{-}$) decay channel of the $\phi$(1020) meson in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV by the STAR experiment. The transverse momentum ($p_{\rm T}$) spectrum is measured for 0.1 $\le p_{\rm T} \le 2.5$ GeV/$c$ at mid-rapidity ($|y|\le1$). We obtain the $p_{\rm T}$-integrated $\phi$(1020) mass $M_{\phi}=1017.7\pm0.8 (\rm {stat.}) \pm0.9 (\rm {sys.})$ MeV/$c^{2}$ and width $\Gamma_{\phi} = 8.0\pm 2.5(\rm {stat.}) \pm 2.3(\rm {sys.}) \textrm{MeV/}c^{2}$, which are within 1.5\,$\sigma$ and 1.1\,$\sigma$ of the vacuum values, respectively. No significant difference is observed in the measured $p_{\rm T}$ spectrum, $dN/dy$, or $\left$ of the $\phi$(1020) meson between the $e^{+}e^{-}$ and hadronic ($K^{+}K^{-}$) decay channels as measured by the same experiment. The experimental results are compared to a theoretical model including medium-modified $\phi$(1020).

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