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16 results on '"E. Korkmaz"'

1. Measurement of theγp→π+nReaction near Threshold

Author

D. M. Skopik, N. R. Kolb, E. Korkmaz, J.C. Bergstrom, D. V. Jordan, Dave Hutcheon, A. K. Opper, G. V. O'Rielly, B.D. Sawatzky, Gerald Feldman, and R. E. Pywell

Subjects
Nuclear physics, Coupling constant, Physics, Dipole, Near threshold, Chiral perturbation theory, Photon, Amplitude, Angular distribution, Pi, General Physics and Astronomy, Atomic physics
Abstract

Differential cross sections for the $\ensuremath{\gamma}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}n$ reaction have been measured at photon energies 1 to 2 MeV above threshold using tagged-photon beams. The electric dipole amplitude ${E}_{0+}$ deduced at threshold is compared to recent predictions from chiral perturbation theory. Constraints on the value of the $\ensuremath{\pi}N$ coupling constant are inferred by combining theory and experiment.

Published
1999
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2. Analyzing Powers and Partial Wave Decomposition ofpn→pp(1S0)π−at Low Energies

Author

F. A. Duncan, S. MayTal-Beck, Daniel Ashery, D. A. Hutcheon, A. Rahav, D.F. Ottewell, D. R. Gill, J.A. Niskanen, J. Aclander, S. Ram, H. Hahn, E. Korkmaz, E.G. Auld, P.L. Walden, R. Weiss, G. Jones, M. E. Sevior, and Murray Moinester

Subjects
Physics, Particle physics, Amplitude, 010308 nuclear & particles physics, Isospin, Partial wave analysis, High Energy Physics::Phenomenology, 0103 physical sciences, Theoretical models, General Physics and Astronomy, 010306 general physics, 01 natural sciences, Decomposition
Abstract

Analyzing powers for $\stackrel{\ensuremath{\rightarrow}}{p}n\ensuremath{\rightarrow}\mathrm{pp}(^{1}S_{0}){\ensuremath{\pi}}^{\ensuremath{-}}$ were measured at beam energies 353, 404, and 440 MeV by extracting the quasifree process from $\stackrel{\ensuremath{\rightarrow}}{p}d\ensuremath{\rightarrow}\mathrm{ppp}{\ensuremath{\pi}}^{\ensuremath{-}}$. Partial wave amplitude analysis yields a significant contribution from the isospin 1, $s$-wave channel. This contribution is relatively much larger than that expected from theoretical models which have been successful in describing the isospin 1, $s$-wave channel behavior of $\mathrm{pp}\ensuremath{\rightarrow}\mathrm{pp}{\ensuremath{\pi}}^{0}$ cross sections at threshold.

Published
1999
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3. Differential Cross Section of thepn→pp(1S0)π−Reaction Extracted frompd→pppπ−

Author

D. A. Hutcheon, H. Hahn, R. Weiss, E. Korkmaz, F. A. Duncan, D.F. Ottewell, D. R. Gill, E.G. Auld, S. MayTal-Beck, S. Ram, M. E. Sevior, Daniel Ashery, C. Aclander, A. Rahav, Murray Moinester, G. Jones, J.A. Niskanen, and P.L. Walden

Subjects
Physics, Scattering cross-section, 010308 nuclear & particles physics, Significant difference, General Physics and Astronomy, 01 natural sciences, Nuclear environment, Angular distribution, Pion, 0103 physical sciences, Production (computer science), Absorption (logic), Atomic physics, 010306 general physics
Abstract

The double differential cross section for $\mathrm{pn}\ensuremath{\rightarrow}\mathrm{pp}{(}^{1}{S}_{0}){\ensuremath{\pi}}^{\ensuremath{-}}$ at three beam energies has been extracted from the quasifree process $\mathrm{pd}\ensuremath{\rightarrow}\mathrm{ppp}{\ensuremath{\pi}}^{\ensuremath{-}}$. A comparison is carried out with single differential cross section measurements for ${}^{3}\mathrm{He}({\ensuremath{\pi}}^{\ensuremath{-}},pn)n$, where the pion is thought to be absorbed onto a $\mathrm{pp}{(}^{1}{S}_{0})$ ``diproton'' state. A significant difference is observed in the shape of the angular distribution between the production and absorption data. This difference is ascribed to the effects of the ${}^{3}\mathrm{He}$ nuclear environment characterizing the absorption process; however, an adequate theoretical explanation is not available.

Published
1998
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4. Precision Measurement of Charge Symmetry Breaking innpElastic Scattering at 347 MeV

Author

R. L. Helmer, A. K. Opper, J. Li, L. Gan, W. T. H. van Oers, P. W. Green, D.C. Healey, L.G. Greeniaus, L. Lee, J.R. Campbell, J. Zhao, R. Abegg, J. Birchall, J. Soukup, N. R. Kolb, P. P. J. Delheij, C. A. Miller, H. Postma, C. D. P. Levy, W. D. Ramsay, S. A. Page, A. N. Zelenski, C. A. Davis, A. Berdoz, E. Korkmaz, and G. M. Stinson

Subjects
Physics, Elastic scattering, Particle physics, Degree (graph theory), Meson, media_common.quotation_subject, General Physics and Astronomy, Charge (physics), Asymmetry, Isospin, High Energy Physics::Experiment, Symmetry breaking, Mirror nuclei, Atomic physics, Nuclear Experiment, media_common
Abstract

Charge symmetry breaking in np elastic scattering at 347 MeV has been measured with high precision. From fits of the measured asymmetry curves over the angular range 53.4{degree} {le} {theta}{sub cm} {le} 86.9{degree}, the difference in the center-of-mass zero-crossing angles of the analyzing powers was determined to be 0.438{degree} {+-} 0.054{degree} (stat.) {+-} 0.051{degree} (syst.). Using the experimentally determined slope of the analyzing power, dA/d{theta} = ({minus}1.35 {+-} 0.05) {times} 10{sup {minus}2} deg{sup {minus}1}, this is equivalent to {Delta}A = [59 {+-} 7(stat.) {+-} 7(syst.) {+-} 2(syst.)] {times} 10{sup {minus}4}. Predictions of nucleon-nucleon interaction models based on meson exchange agree well with this result.

Published
1995
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5. Measurement of np→dπ0cross sections very near threshold

Author

W.C. Olsen, C. A. Miller, L.G. Greeniaus, E. Korkmaz, I. J. van Heerden, D. A. Hutcheon, R. Abegg, G.W.R. Edwards, N.E. Davison, D. J. Mack, Ye Yanlin, and G.A. Moss

Subjects
Physics, Pion, Meson, Computer Science::Information Retrieval, Hadron, General Physics and Astronomy, Elementary particle, Nuclear cross section, Production (computer science), Atomic physics, Particle identification, Delta baryon
Abstract

We have measured {ital np}{r arrow}{ital d}{pi}{sup 0} cross sections at eleven beam energies within 16 MeV of threshold. Total cross sections are only 0.67{plus minus}0.10 of the value which has been generally accepted for {ital s}-wave pion production strength near threshold. The differential cross sections are anisotropic at only 1 MeV (c.m.) above threshold. Our results are compared to {pi}{sup +}d{r arrow}pp data and to predictions of two models.

Published
1990
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6. Charge symmetry breaking in np--dpi(0)

Author

D. V. Jordan, Roger W. Finlay, L.G. Greeniaus, S. D. Reitzner, J.A. Niskanen, T. A. Porcelli, R. Abegg, Dave Hutcheon, G. V. O'Rielly, A. K. Opper, S. Yen, C. A. Davis, P.W. Green, E. Korkmaz, and P. L. Walden

Subjects
Quark, Physics, Particle physics, 010308 nuclear & particles physics, media_common.quotation_subject, General Physics and Astronomy, Observable, Charge (physics), 01 natural sciences, Asymmetry, Neutron temperature, Symmetry (physics), Nuclear physics, 0103 physical sciences, Effective field theory, High Energy Physics::Experiment, Symmetry breaking, Nuclear Experiment, 010306 general physics, media_common
Abstract

The forward-backward asymmetry in np → dπ 0 , which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2 ′ 8.0(stat) ′ 5.5(syst)] × 10 - 4 , at an incident neutron energy of 279.5 MeV. This observable is compared to recent chiral effective field theory calculations, with implications regarding the du quark mass difference.

Published
2003

8. Comment on 'Pion absorption on the diproton'

Author

E. Korkmaz, S. E. Vigdor, and W. W. Jacobs

Subjects
Nuclear physics, Physics, Nuclear reaction, Baryon, Particle physics, Pion, Hadron, General Physics and Astronomy, Elementary particle, Fermion, Nucleon, Absorption (electromagnetic radiation)
Published
1987

9. Determination of the ^{27}Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement.

Author

Androić D, Armstrong DS, Bartlett K, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cornejo JC, Covrig Dusa S, Dalton MM, Davis CA, Deconinck W, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gal C, Gaskell D, Gericke MTW, Gray VM, Grimm K, Guo F, Hoskins JR, Jones DC, Jones MK, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mesick KE, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Narayan A, Ndukum LZ, Nelyubin V, Nuruzzaman, van Oers WTH, Owen VF, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Radloff RW, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Zang P, Zhamkochyan S, Christy ME, Horowitz CJ, Fattoyev FJ, and Lin Z

Abstract

We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst)  ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010  GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157  GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12  fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12  fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15  fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15  fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.

Published
2022
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10. Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering.

Author

Androić D, Armstrong DS, Asaturyan A, Bartlett K, Beaufait J, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cornejo JC, Dusa SC, Dalton MM, Davis CA, Deconinck W, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gal C, Gaskell D, Gericke MTW, Grames J, Gray VM, Grimm K, Guo F, Hoskins JR, Jones D, Jones MK, Jones RT, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey JP, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mei J, Mesick KE, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Narayan A, Ndukum LZ, Nelyubin V, Nuruzzaman, van Oers WTH, Owen VF, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Radloff RW, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Zang P, and Zhamkochyan S

Abstract

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

Published
2020
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11. First determination of the weak charge of the proton.

Author

Androic D, Armstrong DS, Asaturyan A, Averett T, Balewski J, Beaufait J, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cates GD, Cornejo JC, Covrig S, Dalton MM, Davis CA, Deconinck W, Diefenbach J, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gaskell D, Gericke MT, Grames J, Gray VM, Grimm K, Guo F, Hoskins JR, Johnston K, Jones D, Jones M, Jones R, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mei J, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Myers KE, Narayan A, Ndukum LZ, Nelyubin V, Nuruzzaman, van Oers WT, Opper AK, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Poelker M, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Young RD, and Zhamkochyan S

Abstract

The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.

Published
2013
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12. Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering.

Author

Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Allen AH, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Neveling R, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, Van de Wiele J, van Oers WT, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, and Zeps V

Abstract

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A(n) provides a direct probe of the imaginary component of the 2gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

Published
2007
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13. Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment.

Author

Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Hawthorne Allen A, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, MacLachlan GA, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Nakos M, Neveling R, Niccolai S, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, van de Wiele J, van Oers W, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, and Zeps V

Abstract

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.

Published
2005
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14. Charge symmetry breaking in np-->dpi(0).

Author

Opper AK, Korkmaz E, Hutcheon DA, Abegg R, Davis CA, Finlay RW, Green PW, Greeniaus LG, Jordan DV, Niskanen JA, O'Rielly GV, Porcelli TA, Reitzner SD, Walden PL, and Yen S

Abstract

The forward-backward asymmetry in np-->dpi(0), which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2+/-8.0(stat)+/-5.5(syst)]x10(-4), at an incident neutron energy of 279.5 MeV. This observable is compared to recent chiral effective field theory calculations, with implications regarding the du quark mass difference.

Published
2003
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15. Quasifree compton scattering from the deuteron and nucleon polarizabilities

Author

Kolb NR, Rauf AW, Igarashi R, Hornidge DL, Pywell RE, Warkentin BJ, Korkmaz E, Feldman G, and O'Rielly GV

Abstract

Cross sections for quasifree Compton scattering from the deuteron were measured for incident energies of E(gamma) = 236-260 MeV at the laboratory angle straight theta(gamma(')) = -135 degrees. The recoil nucleons were detected in a liquid-scintillator array situated at straight theta(N) = 20 degrees. The measured differential cross sections were used, with the calculations of Levchuk et al., to determine the polarizabilities of the bound nucleons. For the bound proton, the extracted values were consistent with the accepted value for the free proton. Combining our results for the bound neutron with those from Rose et al., we obtain 1-sigma constraints of alpha;(n) = 7.6-14.0 and beta;(n) = 1.2-7.6.

Published
2000
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