Mon·Sep 19, 2016Monday·September 19, 2016

1. 01*

   Strangeness in STAR at RHIC

   Shusu Shi (for the STAR collaboration)🇨🇳

   We present the recent results of strangeness production at the mid-rapidity in Au + Au collisions at RHIC, from $\sqrt{s_{\mathrm{NN}}}$ = 7.7 to 200 GeV. The $v_2$ of multi-strange baryon $\Omega$ and $\varphi$ mesons are similar to that of pions and protons in the intermediate $p_T$ range (2 - 5 GeV/$c$) in $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV Au + Au collisions, indicating that the major part of collective flow has been built up at partonic stage. The breaking of mass ordering between $\varphi$ mesons and protons in the low $p_T$ range ($<$ 1 GeV/$c$) is consistent with a picture that $\varphi$ mesons are less sensitive to later hadronic interaction. The nuclear modification factor $R_{\mathrm{CP}}$ and baryon to meson ratio change dramatically when the collision energy is lower than 19.6 GeV. It suggests a possible change of medium property of the system compared to those from high energies.

   nucl-exJ.Phys.Conf.Ser.(2017)·3 citations
2. 02*

   Nature of low-lying electric dipole resonance excitations in 74Ge

   D. Negi🇿🇦 · M. Wiedeking🇿🇦 · E. G. Lanza🇮🇹 · E. Litvinova🇺🇸 · A. Vitturi🇮🇹 · R. A. Bark · L. A. Bernstein🇺🇸 · D. L. Bleuel🇺🇸 · S. Bvumbi · T. D. Bucher🇿🇦 · B. H. Daub · T. S. Dinoko🇿🇦 and 23 other authors

   Isospin properties of dipole excitations in 74 Ge are investigated using the ({\alpha},{\alpha}'{\gamma}) reaction and compared to ({\gamma},{\gamma}) data. The results indicate that the dipole excitations in the energy region of 6 to 9 MeV adhere to the scenario of the recently found splitting of the region of dipole excitations into two separated parts: one at low energy, being populated by both isoscalar and isovector probes, and the other at high energy, excited only by the electromagnetic probe. Relativistic quasiparticle time blocking approximation (RQTBA) calculations show a reduction in the isoscalar E1 strength with an increase in excitation energy, which is consistent with the measurement.

   nucl-exPRC(2016)·15 citations
3. 03*

   Changes in nuclear structure along the Mn isotopic chain studied via charge radii

   H. Heylen🇧🇪 · C. Babcock🇨🇦 · R. Beerwerth🇩🇪 · J. Billowes🇬🇧 · M.L. Bissell🇧🇪 · K. Blaum🇩🇪 · J. Bonnard🇮🇹 · P. Campbell🇬🇧 · B. Cheal🇬🇧 · T. Day Goodacre🇬🇧 · D. Fedorov🇷🇺 · S. Fritzsche🇩🇪 and 25 other authors

   The hyperfine spectra of ${}^{51,53-64}$Mn were measured in two experimental runs using collinear laser spectroscopy at ISOLDE, CERN. Laser spectroscopy was performed on the atomic $3d^{5}4s^2{}^6{\text{S}}_{5/2}\to 3d^{5}4s4p{}^6{\text{P}}_{3/2}$ and ionic $3d^{5}4s{}^5{\text{S}}_2\to 3d^{5}4p{}^5{\text{P}}_3$ transitions, yielding two sets of isotope shifts. The mass and field shift factors for both transitions have been calculated in the multiconfiguration Dirac-Fock framework and were combined with a King plot analysis in order to obtain a consistent set of mean-square charge radii which, together with earlier work on neutron-deficient Mn, allow the study of nuclear structure changes from $N=25$ across $N=28$ up to $N=39$. A clear development of deformation is observed towards $N=40$, confirming the conclusions of the nuclear moments studies. From a Monte Carlo Shell Model study of the shape in the Mn isotopic chain, it is suggested that the observed development of deformation is not only due to an increase in static prolate deformation but also due to shape fluctuations and triaxiality. The changes in mean-square charge radii are well reproduced using the Duflo-Zuker formula except in the case of large deformation.

   nucl-exPRC(2016)·38 citations
4. 04*

   Physics Program for the STAR/CBM eTOF Upgrade

   The STAR Collaboration · The CBM Collaboration eTOF Group

   The STAR Collaboration and the CBM Collaboration institutions: Heidelberg, Darmstadt, CCNU, Tsinghua, and USTC propose to install an end-cap time-of-flight upgrade (eTOF) to the STAR detector for the RHIC beam energy scan phase II (BES-II) program in 2019 and 2020. BES-II will cover the collision energy range 3.0 to 19.6 GeV. This is the region of interest in the search for a critical point and first-order phase transition, identified by the results from BES-I and by model calculations. For the collider-mode portion of the energy scan, 7.7 to 19.6 GeV, eTOF will extend particle identification (PID) for pions, kaons, and protons to a rapidity of 1.2, complementing the inner Time Projection Chamber (iTPC) upgrade to the forward tracking. The rapidity coverage for PID would extend to only 0.8 without the eTOF upgrade. The eTOF upgrade will enable precision studies of the key bulk property observables, essential to the BES-II search. An internal fixed-target program will allow the energy scan to cover 3.0 to 7.7 GeV. The eTOF upgrade will provide essential mid-rapidity PID for the 4.5 to 7.7 GeV portion of the scan in fixed-target mode. Otherwise there would be a large energy gap in the middle of the BES-II program. A full description of the physics provided by the eTOF upgrade to STAR is presented in this note.

   nucl-ex50 citations
5. 05*

   Heavy flavor Production and Interactions in Relativistic Heavy-Ion Collisions in CMS Experiment

   Wei Xie (for the CMS collaboration)🇺🇸

   This paper presents the CMS measurements of quarkonia and open heavy flavor production in \pp, \pPb, and \PbPb collisions at \sqrtsnn = 2.76 and 5.02 TeV. A brief outlook of the near-future CMS heavy flavor physics analyses is provided at the end.

   nucl-exJ.Phys.Conf.Ser.(2017)·1 citation
6. 06*

   Review of the electric dipole moment of light nuclei

   Nodoka Yamanaka🇯🇵

   In this review, we summarize the theoretical development on the electric dipole moment of light nuclei. We first describe the nucleon level CP violation and its parametrization. We then present the results of calculations of the EDM of light nuclei in the ab initio approach and in the cluster model. The analysis of the effect of several models beyond standard model is presented, together with the prospects for its discovery. The advantage of the electric dipole moment of light nuclei is focused in the point of view of the many-body physics. The evaluations of the nuclear electric dipole moment generated by the $\theta$-term and by the CP phase of the Cabibbo-Kobayashi-Maskawa matrix are also reviewed.

   ↳ nucl-thhep-exhep-phnucl-exIJMPE(2017)·59 citations
7. 07*

   Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in $p$$+$$p$ collisions at $\sqrt{s}$=510 GeV

   A. Adare · C. Aidala · N.N. Ajitanand · Y. Akiba · R. Akimoto · J. Alexander · M. Alfred · V. Andrieux · K. Aoki · N. Apadula · Y. Aramaki · H. Asano and 456 other authors

   Dihadron and isolated direct photon-hadron angular correlations are measured in $p$$+$$p$ collisions at $\sqrt{s}=510$ GeV. Correlations of charged hadrons of $0.7<p_T<10$ GeV/$c$ with ${\pi }^0$ mesons of $4<p_T<15$ GeV/$c$ or isolated direct photons of $7<p_T<15$ GeV/$c$ are used to study nonperturbative effects generated by initial-state partonic transverse momentum and final-state transverse momentum from fragmentation. The nonperturbative behavior is characterized by measuring the out-of-plane transverse momentum component $p_{\mathrm{out}}$ perpendicular to the axis of the trigger particle, which is the high-$p_T$ direct photon or ${\pi }^0$. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta ($p_T^{\mathrm{trig}}$). The Gaussian widths and root mean square of $p_{\mathrm{out}}$ are reported as a function of the interaction hard scale $p_T^{\mathrm{trig}}$ to investigate possible transverse-momentum-dependent evolution differences between the ${\pi }^0$-h${}^{\pm }$ and direct photon-h${}^{\pm }$ correlations and factorization breaking effects. The widths are found to decrease with $p_T^{\mathrm{trig}}$, which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in $p$$+$$p$ collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.

   ↳ hep-exnucl-exPRD(2017)·23 citations
8. 08*

   Updates to the p+p and A+A chemical freeze-out lines from the new experimental data

   V. V. Begun🇵🇱 · V. Vovchenko🇩🇪 · M. I. Gorenstein🇺🇦

   We show that the new data on mean multiplicities measured in p+p and A+A collisions together with the updated list of resonances lead to the significant changes of the obtained freeze-out lines. The new A+A line gives much smaller temperatures at high collision energies and agrees with the values obtained at the LHC. The newly obtained p+p line is much closer to the A+A line than previously expected, and even touches it in the region where the $K^{+}/{\pi }^{+}$ horn appears in the data. It indicates that the temperatures that will be obtained in the beam energy and system size scan by the NA61/SHINE Collaboration might be very close. However, our analysis shows that the chemical potentials could be very different for the same energies in A+A and p+p. It adds more puzzles to the set of surprising coincidences at the energies close to the possible onset of deconfinement.

   ↳ nucl-thhep-exhep-phnucl-exJ.Phys.Conf.Ser.(2017)·12 citations
9. 09*

   Heavy flavor production in heavy-ion collisions from soft collinear effective theory

   Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸

   We review a new approach to open heavy flavor production in heavy ion collisions based on Soft Collinear Effective Theory (SCET). We include both finite heavy quark masses in the SCET Lagrangian and Glauber gluons that describe the interaction of collinear partons with the hot and dense QCD medium. From the new effective field theory, we derive massive in-medium splitting kernels and propose a new framework for including in-medium interactions consistent with next-to-leading order calculations in QCD. We present numerical results for the suppression of $D$- and $B$-mesons and compare to results obtained within the traditional approach to parton energy loss. We find good agreement when comparing to existing data from the LHC at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV and 2.76 TeV.

   ↳ hep-phhep-exnucl-exJ.Phys.Conf.Ser.(2017)·3 citations
10. 10*

    Photoproduction of a large invariant mass $\gamma \rho$ pair at small momentum transfer

    R. Boussarie🇫🇷 · B. Pire🇫🇷 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷

    The collinear factorization framework allows to describe the exclusive photoproduction of a $\gamma \rho$ pair in the generalized Bjorken regime in terms of a perturbatively calculable coefficient function and universal generalized parton distributions. The kinematics are defined by a large invariant mass of the $\gamma \rho$ pair and a small transverse momentum of the final nucleon. We calculate the scattering amplitude at leading order in ${\alpha }_s$ and the differential cross sections for the process where the $\rho -$meson is either longitudinally or transversely polarized, in the kinematics of the near future Jlab experiments. Our estimate of the cross section demonstrates that this process is measurable at JLab 12-GeV.

    ↳ hep-phhep-exnucl-exnucl-thPoS(2016)·0 citations
11. 11*

    Progress of the Felsenkeller shallow-underground accelerator for nuclear astrophysics

    D. Bemmerer🇩🇪 · F. Cavanna🇮🇹 · T.E. Cowan🇩🇪 · M. Grieger🇸🇪 · T. Hensel🇩🇪 · A.R. Junghans🇩🇪 · F. Ludwig🇩🇪 · S. E. Müller🇩🇪 · B. Rimarzig · S. Reinicke🇩🇪 · S. Schulz · R. Schwengner🇩🇪 and 6 other authors

    Low-background experiments with stable ion beams are an important tool for putting the model of stellar hydrogen, helium, and carbon burning on a solid experimental foundation. The pioneering work in this regard has been done by the LUNA collaboration at Gran Sasso, using a 0.4 MV accelerator. In the present contribution, the status of the project for a higher-energy underground accelerator is reviewed. Two tunnels of the Felsenkeller underground site in Dresden, Germany, are currently being refurbished for the installation of a 5 MV high-current Pelletron accelerator. Construction work is on schedule and expected to complete in August 2017. The accelerator will provide intense, 50 uA, beams of 1H+, 4He+, and 12C+ ions, enabling research on astrophysically relevant nuclear reactions with unprecedented sensitivity.

    ↳ physics.ins-detnucl-exJPS Conf.Proc.(2017)·1 citation
12. 12*

    The physics mechanisms of light and heavy flavor $v_2$ and mass ordering in AMPT

    Hanlin Li🇨🇳 · Zi-Wei Lin🇺🇸 · Fuqiang Wang🇺🇸

    A Multi-Phase Transport (AMPT) model has been shown to describe experimental data well, such as the bulk properties of particle spectra and elliptic anisotropy ($v_2$) in heavy ion collisions. Recent studies have shown that AMPT describes the $v_2$ data in small system collisions as well. In these proceedings, we first investigate the origin of the mass ordering of identified hadrons $v_2$ in heavy ion as well as small system collisions. We then study the production mechanism of the charm $v_2$ in light of the escape mechanism for the light quark $v_2$.

    ↳ nucl-thnucl-exJ.Phys.Conf.Ser.(2017)·2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.