Nuclear Theory·nucl-th

Tuesday·March 10, 2015

12 papers—5 primary·7 cross-listed

06
QCD description of backward vector meson hard electroproduction
B. Pire🇫🇷 · K. Semenov-Tian-Shansky🇫🇷 · L. Szymanowski🇵🇱
We consider backward vector meson exclusive electroproduction off nucleons in the framework of collinear QCD factorization. Nucleon to vector meson transition distribution amplitudes arise as building blocks for the corresponding factorized amplitudes. In the near-backward kinematics, the suggested factorization mechanism results in the dominance of the transverse cross section of vector meson production ( $σ_{T} ≫ σ_{L}$ ) and in the characteristic $1/ Q^{8}$ -scaling behavior of the cross section. We evaluate nucleon to vector meson TDAs in the cross-channel nucleon exchange model and present estimates of the differential cross section for backward $ρ^{0}$ , $ω$ and $ϕ$ meson production off protons. The resulting cross sections are shown to be measurable in the forthcoming JLab@12 GeV experiments.
↳ hep-phhep-exnucl-exnucl-thPRD(2015)·21 citations
07
Quantum-mechanical picture of peripheral chiral dynamics
C. Granados🇸🇪 · C. Weiss🇺🇸
The nucleon's peripheral transverse charge and magnetization densities are computed in chiral effective field theory. The densities are represented in first-quantized form, as overlap integrals of chiral light-front wave functions describing the transition of the nucleon to soft pion-nucleon intermediate states. The orbital motion of the pion causes a large left-right asymmetry in a transversely polarized nucleon. The effect attests to the relativistic nature of chiral dynamics [pion momenta k = O(M_pi)] and could be observed in form factor measurements at low momentum transfer.
↳ hep-phnucl-thPRC(2015)·8 citations
08
Scrutinizing the eta-eta' mixing, masses and pseudoscalar decay constants in the framework of U(3) chiral effective field theory
Xu-Kun Guo🇨🇳 · Zhi-Hui Guo🇨🇳 · Jose Antonio Oller🇪🇸 · Juan Jose Sanz-Cillero🇪🇸
We study the $η$ - $η^{'}$ mixing up to next-to-next-to-leading-order in $U (3)$ chiral perturbation theory in the light of recent lattice simulations and phenomenological inputs. A general treatment for the $η$ - $η^{'}$ mixing at higher orders, with the higher-derivative, kinematic and mass mixing terms, is addressed. The connections between the four mixing parameters in the two-mixing-angle scheme and the low energy constants in the $U (3)$ chiral effective theory are provided both for the singlet-octet and the quark-flavor bases. The axial-vector decay constants of pion and kaon are studied in the same order and confronted with the lattice simulation data as well. The quark-mass dependences of $m_{η}$ , $m_{η^{'}}$ and $m_{K}$ are found to be well described at next-to-leading order. Nonetheless, in order to simultaneously describe the lattice data and phenomenological determinations for the properties of light pseudoscalars $π, K, η$ and $η^{'}$ , the next-to-next-to-leading order study is essential. Furthermore, the lattice and phenomenological inputs are well reproduced for reasonable values of low the energy constants, compatible with previous bibliography.
↳ hep-phhep-exhep-latnucl-thJHEP(2015)·73 citations
09
Neutron skin and centrality classification in high-energy heavy-ion collisions at the LHC
Hannu Paukkunen🇫🇮
The concept of centrality in high-energy nuclear collisions has recently become a subject of an active debate. In particular, the experimental methods to determine the centrality that have given reasonable results for many observables in high-energy lead-lead collisions at the LHC have led to surprising behaviour in the case of proton-lead collisions. In this letter, we discuss the possibility to calibrate the experimental determination of centrality by asymmetries caused by mutually different spatial distributions of protons and neutrons inside the nuclei --- a well-known phenomenon in nuclear physics known as the neutron-skin effect.
↳ hep-phhep-exnucl-exnucl-thPLB(2015)·32 citations
10
Study of the $f_{2} (1270)$ , $f_{2}^{'} (1525)$ , $K ˉ_{2}^{*} (1430)$ , $f_{0} (1370)$ and $f_{0} (1710)$ production from $ψ (n S)$ and $Υ (n S)$ decays
Lian-Rong Dai🇨🇳 · Ju-Jun Xie🇨🇳 · E. Oset🇨🇳
Based on previous studies that support the important role of the $f_{2} (1270)$ , $f_{2}^{'} (1525)$ , and $K ˉ_{2}^{*} (1430)$ resonances in the $J / ψ [ψ (2 S)] \to ϕ (ω) V V$ decays, we make an analysis of the analogous decays of $Υ (1 S)$ and $Υ (2 S)$ , taking into account recent experimental data. In addition, we study the $J / ψ$ and $ψ (2 S)$ radiative decays and we also made predictions for the radiative decay of $Υ (1 S)$ and $Υ (2 S)$ into $γ f_{2} (1270)$ , $γ f_{2}^{'} (1525)$ , $γ f_{0} (1370)$ and $γ f_{0} (1710)$ , comparing with the recent results of a CLEO experiment. We can compare our results for ratios of decay rates with eight experimental ratios and find agreement in all but one case, where experimental problems are discussed.
↳ hep-phhep-exnucl-thPRD(2015)·18 citations
11
Energy Dependence of Moments of Net-Proton and Net-Charge Multiplicity Distributions at STAR
Xiaofeng Luo (for the STAR Collaboration)🇨🇳
We present the energy dependence of moments of net-proton and net-charge multiplicity distributions in Au+Au collisions measured by the STAR experiment in the first phase of the Beam Energy Scan (BES) at the Relativistic Heavy Ion Collider (RHIC). By using the time of flight detector for particle identification, the upper transverse momentum ( $p_{T}$ ) limit for proton and anti-proton is extended from 0.8 GeV/c up to 2 GeV/c. The $p_{T}$ and rapidity acceptance dependence study for the moments of net-proton distribution show that the larger the acceptance is, the greater the deviation from unity. The most pronounced structure is found in the energy dependence of {\KV} of net-proton distributions from the $0 \sim 5$ most central collisions within $0.4 < p_{T} < 2$ GeV/c and at mid-rapidity $∣ y ∣ < 0.5$ . At energies above 39 GeV, the values of {\KV} are close to unity and for energies below 39 GeV, it shows significant deviation below unity around 19.6 and 27 GeV, then a large increase above unity is observed at 7.7 GeV.
↳ nucl-exhep-exhep-phnucl-thPoS(2015)·188 citations
12
Parity violating effects in an exotic perturbation of the rigid rotator
A. Pallares Rivera🇲🇽 · M. Kirchbach🇲🇽
The perturbation of the free rigid rotator by the trigonometric Scarf potential is shown to conserve its energy excitation patterns and change only the wave functions towards spherical harmonics rescaled by a function of an unspecified parity, or mixtures of such rescaled harmonics of equal magnetic quantum numbers and different angular momenta. In effect, no parity can be assigned to the states of the rotational bands emerging in this exotic way, and the electric dipole operator is allowed to acquire non-vanishing expectation values.
↳ quant-phhep-phnucl-thEur.Phys.J.Plus(2015)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

QCD description of backward vector meson hard electroproduction

Quantum-mechanical picture of peripheral chiral dynamics

Scrutinizing the eta-eta' mixing, masses and pseudoscalar decay constants in the framework of U(3) chiral effective field theory

Neutron skin and centrality classification in high-energy heavy-ion collisions at the LHC

Study of the f2​(1270), f2′​(1525), Kˉ2∗​(1430), f0​(1370) and f0​(1710) production from ψ(nS) and Υ(nS) decays

Energy Dependence of Moments of Net-Proton and Net-Charge Multiplicity Distributions at STAR

Parity violating effects in an exotic perturbation of the rigid rotator

Affiliations

Study of the $f_{2} (1270)$ , $f_{2}^{'} (1525)$ , $K ˉ_{2}^{*} (1430)$ , $f_{0} (1370)$ and $f_{0} (1710)$ production from $ψ (n S)$ and $Υ (n S)$ decays