Search

Background: Until now the knowledge about nucleon resonances with a mass higher than 2 GeV has been scarce. Huge amounts of experimental data of the multipion photoproduction have been accumulated, and more can be expected in the future in facilities such as JLab 12 GeV. It makes it possible to investigate the decay of a nucléon resonance into another nucleon resonance. Purpose: The possibility to research the decay of the N(2120) to nucleon resonances near 1.7 GeV in the three-pion photoproduction will be explored to provide useful information for future experimental study. Method: The pion and radiative decay amplitudes of nucleon resonances are studied within the constituent quark model, which is used to calculate the couplings constants, especially for the decay of a nucleon resonance near 2.1 GeV to another nucleon resonance near 1.7 GeV. The three-pion photoproduction off the neutron target, i.e., γn n→ π-π- Δ++ → π-π-π+ p, is investigated based on the effective Lagrangian method with the coupling constant obtained form the decay amplitudes. Results: The resonance contribution with a state N(²PM)3/2 near 2.1 GeV decaying to a state N(4PM)5/2 near 1.7 GeV, i.e., N(2120) → N(1675)π, is dominant in the process considered. The total cross section from the resonance contribution is at the order of 1 μb and can be easily distinguished from the background. Conclusions: Our results suggest it is practicable to research the decay of the N(2120) to the N(1675) in experiment. [ABSTRACT FROM AUTHOR]

A recent proposed universal decay law (UDL) for a-decay and cluster radioactivity (CR) half-lives [C. Qi, F. R. Xu, R. J. Liotta, and R. Wyss, Phys. Rev. Lett 103, 072501 (2009)] that can accurately reproduce the experimental data was introduced starting from α-like R-matrix theory. The UDL formula depends only on the mass and charge numbers of the charged particle and the Q value. The new mass table AME2012 and the theoretical FRDM95, KTUY05, and WS2011 masses are used to determine the Q values. We systematically investigate the branching ratios of cluster radioactivity with respect to a decay for even-even superheavy nuclei (SHN) with Z = 104-120 using the UDL formula. It is found that cluster radioactivity can be compared to α decay in neutron-rich SHN. [ABSTRACT FROM AUTHOR]

With nonrelativistic QCD factorization, we present the first complete next-to-leading order study on the polarization of prompt J/ψ hadroproduction by including feeddown from χc(3PJ1, 3S18) and ψ(2s) which turn out to be very important parts. By using the color-octet long-distance matrix elements obtained from a combined fit of the measurements at the Tevatron and LHC for J/ψ, ψ(2s) and χc the prompt J/ψ polarization predictions are presented, and the results are in agreement with the CDF run I data (except two points), but in conflict with the CDF run II data, while they are close to the ALICE data (inclusive J/ψ). The measurements at the LHC are expected to clarify the situation. [ABSTRACT FROM AUTHOR]

There is lively debate on whether Asian plate material was involved in southward flow of mid-lower crust in a ductile channel beneath southern Tibet. One argument against such involvement is the apparent absence of material derived from Asian lithosphere within the High Himalayan Series (Indian plate) that could represent the putative channel. A north-south—trending mid-Miocene dike swarm that intrudes the Tethyan sedimentary cover of the Sakya gneiss dome (Indian plate) yields new Sr-Nd isotopic data (87Sr/86Sr = 0.7071-0.7079; ϵNd -4 to -6) indicating that these melts share the same source as Miocene dacitic dikes from north of the Indus-Tsangpo suture. Moreover, dikes on both sides of this suture represent crustal melts derived largely from mid-lower crust of the Asian plate, exposed today as the Nyainqentanglha gneisses that underlie the Gangdese batholith. We infer that melting of the Asian lithosphere extended south of the surface trace of the suture, requiring southward propagation of anatectic Asian middle crustal material during the Miocene. The emplacement ages of the southern dike swarm (12-9 Ma) thus delimit the timing of active southward ductile flow of Asian material. [ABSTRACT FROM AUTHOR]

We argue that the large suppression of the ψ(2S) inclusive cross section relative to the J/ψ inclusive cross section in proton-nucleus (p+A) collisions can be attributed to factorization breaking effects in the formation of quarkonium. These factorization breaking effects arise from soft color exchanges between charm-anticharm pairs undergoing hadronization and comoving partons that are long lived on time scales of quarkonium formation. We compute the short distance pair production of heavy quarks in the color glass condensate (CGC) effective field theory and employ an improved color evaporation model (ICEM) to describe their hadronization into quarkonium at large distances. The combined CGC+ICEM model provides a quantitative description of J/ψ and ψ(2S) data in proton-proton (p+p) collisions from both RHIC and the LHC. Factorization breaking effects in hadronization, due to additional parton comovers in the nucleus, are introduced heuristically by imposing a cutoff Λ, representing the average momentum kick from soft color exchanges, in the ICEM. Such soft exchanges have no perceptible effect on J/ψ suppression in p+A collisions. In contrast, the interplay of the physics of these soft exchanges at large distances, with the physics of semihard rescattering at short distances, causes a significant additional suppression of ψ(2S) yields relative to that of the J/ψ. A good fit of all RHIC and LHC J/ψ and ψ(2S) data, for transverse momenta P⊥≤5 GeV in p+p and p+A collisions, is obtained for Λ∼10 MeV. [ABSTRACT FROM AUTHOR]

Within the improved Weizsäcker-Skyrme (WS)-type nuclear mass formulas, we systematically calculated one-nucleon and two-nucleon separated energy, α-decay and ß-decay energies, and the odd-even staggering (OES) of nuclear binding energies. As a result, the root-mean-square (rms) deviations of 2267 nuclei within the new improved WS-type mass formula are dropped from 493 to 167 keV, where 2267 nuclei are extracted from the atomic mass evaluation of 2012. Simultaneously, all the rms deviations of one-nucleon and two-nucleon separation energies and decay energies Qα, Qβ-, Qβ+, and QEC for more than 3000 nuclei are cut down by about 100-400 keV. Further, some basic physical observations of 988 boundary nuclei are predicted for providing reference to experiments. Finally, the overall neutron OESs and proton OESs have been systemically investigated and the residual error satisfies a normal distribution. The pairing gaps Δn and Δp of the isotopes of O, Ca, Ni, Zr, Sn, Gd, Qs, Pb, Pa, Ds and the isotonic magic chains of N = 28, 50, 82, 126 and even-even nuclei are also studied with dramatic improvements obtained. Especially, the rms of Δn and Δp in these nuclei have been reduced by about 200 keV. The above physical quantities show important information for nuclear charts and the features of nuclear structure. [ABSTRACT FROM AUTHOR]

Based on the nonrelativistic QCD factorization scheme, we present the first complete next-to-leading-order study on the yield and polarization of ?(1S,2S,3S) hadroproduction. By using the color-octet long-distance matrix elements obtained from fits of the experimental measurements on ? yield and polarization at the Tevatron and LHC, our results can explain the measurements on the yield very well, and for the polarizations of ?(1S,2S,3S), they are in (good, good, bad) agreement with recent CMS measurement, but still have some distance from the CDF measurement. [ABSTRACT FROM AUTHOR]

Quantum physics allows for unconditionally secure communication between parties that trust each other. However, when the parties do not trust each other such as in the bit commitment scenario, quantum physics is not enough to guarantee security unless extra assumptions are made. Unconditionally secure bit commitment only becomes feasible when quantum physics is combined with relativistic causality constraints. Here we experimentally implement a quantum bit commitment protocol with relativistic constraints that offers unconditional security. The commitment is made through quantum measurements in two quantum key distribution systems in which the results are transmitted via free-space optical communication to two agents separated with more than 20 km. The security of the protocol relies on the properties of quantum information and relativity theory. In each run of the experiment, a bit is successfully committed with less than 5.68 × 10-2 cheating probability. This demonstrates the experimental feasibility of quantum communication with relativistic constraints. [ABSTRACT FROM AUTHOR]