Nuclear Theory·nucl-th

Wednesday·January 24, 2018

12 papers—7 primary·5 cross-listed

08
Total and differential cross sections of $η$ -production in proton-deuteron fusion for excess energies between $Q_{η} = 13 MeV$ and $Q_{η} = 81 MeV$
P. Adlarson🇸🇪 · W. Augustyniak🇵🇱 · W. Bardan🇵🇱 · M. Bashkanov🇬🇧 · F. S. Bergmann🇩🇪 · M. Berłowski🇵🇱 · A. Bondar🇷🇺 · M. Büscher🇩🇪 · H. Calén🇸🇪 · I. Ciepał🇵🇱 · H. Clement🇩🇪 · E. Czerwiński🇵🇱 and 81 other authors
New data on both total and differential cross sections of the production of $η$ mesons in proton-deuteron fusion to $^{3} He η$ in the excess energy region $13.6 MeV \leq Q_{η} \leq 80.9 MeV$ are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Jülich, using a proton beam at 15 different beam momenta between $p_{p} = 1.60 GeV / c$ and $p_{p} = 1.74 GeV / c$ . While significant structure of the total cross section is observed in the energy region $20 MeV ≲ Q_{η} ≲ 60 MeV$ , a previously reported sharp variation around $Q_{η} \approx 50 MeV$ cannot be confirmed. Angular distributions show the typical forward-peaking that was reported elsewhere. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a large interval.
↳ nucl-exnucl-thPLB(2018)·14 citations
09
Charm production in interactions of antiproton with proton and nuclei at $P ˉ A N D A$ energies
R. Shyam🇮🇳 · K. Tsushima🇧🇷
We study the production of charmed baryons in the antiproton-proton and antiproton-nucleus interactions within a fully covariant model that is based on an effective Lagrangian approach. The baryon production proceeds via the $t$ -channel $D^{0}$ and $D^{* 0}$ meson-exchange diagrams. We have also explored the production of the charm-baryon hypernucleus $_{Λ_{c}^{+}}^{16}$ O in the antiproton - $^{16}$ O collisions. For antiproton beam momenta of interest to the $P ˉ A N D A$ experiment, the 0 $^{\circ}$ differential cross sections for the formation of $_{Λ_{c}^{+}}^{16}$ O hypernuclear states with simple particle-hole configurations, have magnitudes in the range of a few $μ$ b/sr.
↳ hep-phhep-exnucl-exnucl-thFew Body Syst.(2018)·4 citations
10
Pulsar glitch and nuclear EoS: Applicability of superfluid model
A. Li · R. Wang
In this contribution, we have made use of the contemporary equation of states (EOSs) for the complete neutron star structure, and confronted them with one particular glitch constrain for the crustal moment of inertia (MOI). We find that with these EOSs, the radii of three millisecond pulsars selected by NICER: PSR J0437-4715, PSR J1614-2230, PSR J0751+1807, are all around 12.5 km. Also, a star with $M ≲ 1.55 M_{⊙}$ would fulfill the MOI calculation for glitch constrain with the latest neutron superfluidity density, and the glitch crisis might not be present.
↳ astro-ph.HEnucl-thIAU Symp.(2017)·3 citations
11
Baryon-antibaryon dynamics in relativistic heavy-ion collisions
Eduard Seifert🇩🇪 · Wolfgang Cassing🇩🇪
The dynamics of baryon-antibaryon annihilation and reproduction ( $B B ˉ \leftrightarrow 3 M$ ) is studied within the Parton-Hadron-String Dynamics (PHSD) transport approach for Pb+Pb and Au+Au collisions as a function of centrality from lower Super Proton Synchrotron (SPS) up to Large Hadron Collider (LHC) energies on the basis of the quark rearrangement model (QRM). At Relativistic Heavy-Ion Collider (RHIC) energies we find a small net reduction of baryon-antibaryon ( $B B ˉ$ ) pairs while for the LHC energy of $s_{N N}$ = 2.76 GeV a small net enhancement is found relative to calculations without annihilation (and reproduction) channels. Accordingly, the sizeable difference between data and statistical calculations in Pb+Pb collisions at $s_{N N}$ = 2.76 TeV for proton and antiproton yields \cite{53}, where a deviation of 2.7 $σ$ was claimed by the ALICE Collaboration, should not be attributed to a net antiproton annihilation. This is in line with the observation that no substantial deviation between the data and statistical hadronization model (SHM) calculations is seen for antihyperons, since according to the PHSD analysis the antihyperons should be modified by the same amount as antiprotons. As the PHSD results for particle ratios are in line with the ALICE data (within error bars) this might point towards a deviation from statistical equilibrium in the hadronization (at least for protons/antiprotons). Furthermore, we find that the $B B ˉ \leftrightarrow 3 M$ reactions are more effective at lower SPS energies where a net suppression for antiprotons and antihyperons up to a factor of 2 -- 2.5 can be extracted from the PHSD calculations for central Au+Au collisions.
↳ hep-phnucl-thPRC(2018)·18 citations
12
Spin-1 particles and perturbative QCD
J. P. B. C. de Melo (LFTC - Cruzeiro do Sul)🇧🇷 · T. Frederico (Instituto Tecnológico de Aeronáutica - ITA)🇧🇷 · Chueng -R. Ji (Departament of Physics, North Carolina State University, NCSU)🇺🇸
Due to the angular condition in the light-front dynamics (LFD), the extraction of the electromagnetic form factors for spin-1 particles can be uniquely determined taking into account implicitly non-valence and/or the zero-mode contributions to the matrix elements of the electromagnetic current. No matter which matrix elements of the electromagnetic current is used to extract the electromagnetic form factors, the same unique result is obtained. As physical observables, the electromagnetic form factors obtained from matrix elements of the current in LFD must be equal to those obtained in the instant form calculations. Recently, the Babar collaboration \cite{Aubert2008} has analyzed the reaction $e^{+} e^{-} \to ρ^{+} + ρ^{-}$ at $s = 10.58 G e V$ to measure the cross section as well as the ratios of the helicity amplitudes $F_{λ^{'} λ}$ . We present our recent analysis of the Babar data for the rho meson considering the angular condition in LFD to put a stringent test on the onset of asymptotic perturbative QCD and predict the energy regime where the subleading contributions are still considerable.
↳ hep-phhep-exhep-thnucl-ex+1Few Body Syst.(2018)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Total and differential cross sections of η-production in proton-deuteron fusion for excess energies between Qη​=13MeV and Qη​=81MeV

Charm production in interactions of antiproton with proton and nuclei at PˉANDA energies

Pulsar glitch and nuclear EoS: Applicability of superfluid model

Baryon-antibaryon dynamics in relativistic heavy-ion collisions

Spin-1 particles and perturbative QCD

Affiliations

Total and differential cross sections of $η$ -production in proton-deuteron fusion for excess energies between $Q_{η} = 13 MeV$ and $Q_{η} = 81 MeV$

Charm production in interactions of antiproton with proton and nuclei at $P ˉ A N D A$ energies