Wed·Nov 30, 2016Wednesday·November 30, 2016

1. 01*

   Experimental summary for heavy flavor production

   Rongrong Ma🇺🇸

   Measurements of heavy flavor production in heavy-ion collisions have played an important role in understanding the properties of the quark-gluon plasma created in such collision. Due to their large masses, heavy flavor quarks present unique sensitivity to the kinematics as well as the dynamics of the hot and dense medium. In this article, a selection of recent measurements on heavy flavor production in p+p, p+A and A+A collisions at both RHIC and LHC energies will be presented. The measurements in p+p collisions serve as benchmarks to fundamental theories, and as references to similar studies in A+A collisions where the hot medium effects are present. On the other hand, the measurements in p+A collisions can help to quantify the cold nuclear matter effects which are also in effect in A+A collisions and thus need to be taken into account when interpreting the measurements in heavy-ion collisions. The experimental results from A+A collisions are discussed and compared to theoretical calculations, which can shed lights on the understanding of the quark-gluon plasma.

   nucl-exJ.Phys.Conf.Ser.(2017)·0 citations
2. 02*

   Nucleon-Nucleon Correlations, Short-lived Excitations, and the Quarks Within

   O. Hen🇺🇸 · G. A. Miller🇺🇸 · E. Piasetzky🇮🇱 · L. B. Weinstein🇺🇸

   This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. We focus on the interpretation of measurements of the EMC effect for valence quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRC that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein.

   nucl-exhep-phnucl-thRMP(2017)·420 citations
3. 03*

   Phenomenological analysis of associated production of $Z^0+b$ in the $b\to J/\psi X$ decay channel at the LHC

   Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇨🇭

   The ATLAS collaboration recently reported on the first observation of associated-production of a $Z^0$ boson with a $J/\psi$. We recently claimed that the corresponding yield of the {\it prompt} $J/\psi$ was dominated by double parton scatterings in the ATLAS acceptance with a somewhat small value of ${\sigma }_{\mathrm{eff}}$. We also found out that single parton scatterings were only dominant at large transverse momenta. We present here the first phenomenological analysis of another part of the ATLAS data sample, namely of a $Z^0$ boson plus a {\it non-prompt} $J/\psi$. Our study is performed at next-to-leading order in ${\alpha }_s$ and includes parton-shower effects via the {\sc\small MadGraph5_aMC@NLO} framework. We find out that the data, unlike the case of prompt $J/\psi +Z^0$, do not hint at significant DPS contributions. Owing to the current experimental and theoretical uncertainties, there is still a room for these but with a lower limit of ${\sigma }_{\mathrm{eff}}$ close to 5 mb. We stress the importance of QCD corrections to account for the ATLAS data.

   ↳ hep-phhep-exnucl-exnucl-thNPB(2017)·30 citations
4. 04*

   The branching ratio $\omega \to {\pi }^{+}{\pi }^{-}$ revisited

   C. Hanhart🇩🇪 · S. Holz🇩🇪 · B. Kubis🇩🇪 · A. Kupść🇸🇪 · A. Wirzba🇩🇪 · C. W. Xiao🇩🇪

   We analyze the most recent data for the pion vector form factor in the timelike region, employing a model-independent approach based on dispersion theory. We confirm earlier observations about the inconsistency of different modern high-precision data sets. Excluding the BaBar data, we find an updated value for the isospin-violating branching ratio $\mathcal{B}(\omega \to {\pi }^{+}{\pi }^{-})=(1.46\pm 0.08)\times 10^{-2}$. As a side result, we also extract an improved value for the pion vector or charge radius, $\sqrt{⟨r_V^2⟩}=0.6603(5)(4)\text{fm}$, where the first uncertainty is statistical as derived from the fit, while the second estimates the possible size of nonuniversal radiative corrections. In addition, we demonstrate that modern high-quality data for the decay ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}\gamma$ will allow for an even improved determination of the transition strength $\omega \to {\pi }^{+}{\pi }^{-}$.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2017)·71 citations
5. 05*

   Hadron tomography studies by generalized parton distributions and distribution amplitudes

   S. Kumano🇯🇵

   We discuss hadron-tomography studies for the nucleon and exotic hadrons by high-energy hadron reactions. First, the constituent-counting rule is explained for determining internal quark configurations of exotic-hadron candidates by scaling properties of high-energy exclusive cross sections. Next, possibilities are discussed for investigating the generalized parton distributions (GPDs) of the nucleon and exotic hadrons at J-PARC. In particular, we study hadronic $2\to 3$ process $p+p\to N+\pi +B$, exclusive Drell-Yan process, and exotic-hadron GPDs. For determining three-dimensional structure of unstable exotic hadrons, we consider $s$-$t$ crossed quantities of the GPDs called generalized distribution amplitudes (GDAs), which can be investigated at KEKB. We explain possible studies of the GDAs by two-photon processes.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJ Web Conf.(2017)·1 citation
6. 06*

   Behavior of a trapezoid-based data acquisition system up to 100 kHz and beyond

   Stefan Schmidt🇩🇪 · Tanja Heftrich🇩🇪 · Jan Glorius🇩🇪 · Gabriele Hampel · Ralf Plag🇩🇪 · René Reifarth🇩🇪 · Zuzana Slavkovská🇩🇪 · Kerstin Sonnabend🇩🇪 · Christian Stieghorst · Norbert Wiehl · Stephan Zauner

   In this work, we investigated the ability of a high-purity germanium detector connected to a trapezoid-filter-based data acquisition system to reliably record signals in spite of high sample activities. By activating multiple Na${}_2$CO${}_3$ samples with different Na content, we were able to deduce efficiency, resolution and dead time of the system used as a function of the sample activity. Based on the results, we were able to find a setting which allows measurements of event rates up to 35~kHz per readout channel with an energy resolution of 0.3\% at the 2754 keV ${}^{24}$Na line.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2014)·1 citation
7. 07*

   Inclusive breakup of three-fragment weakly bound nuclei

   Brett V. Carlson🇧🇷 · Tobias Frederico🇧🇷 · Mahir S. Hussein🇧🇷

   The inclusive breakup of three-fragment projectiles is discussed within a four-body spectator model. Both the elastic breakup and the non-elastic breakup are obtained in a unified framework. Originally developed in the 80's for two-fragment projectiles such as the deuteron, in this paper the theory is successfully generalized to three-fragment projectiles. The expression obtained for the inclusive cross section allows the extraction of the incomplete fusion cross section, and accordingly generalizes the surrogate method to cases such as (t,p) and (t,n) reactions. It is found that two-fragment correlations inside the projectile affect in a conspicuous way the elastic breakup cross section. The inclusive non-elastic breakup cross section is calculated and is found to contain the contribution of a three-body absorption term that is also strongly influenced by the two-fragment correlations. This latter cross section contains the so-called incomplete fusion where more than one compound nuclei are formed. Our theory describes both stable weakly bound three-fragment projectiles and unstable ones such as the Borromean nuclei.

   ↳ nucl-thnucl-exPLB(2017)·25 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.