Wed·May 24, 2017Wednesday·May 24, 2017

1. 01*

   Highlights from BNL and RHIC 2016

   M. J. Tannenbaum🇺🇸

   Highlights of news from Brookhaven National Laboratory (BNL) and results from the Relativistic Heavy Ion Collider (RHIC) in the period July 2015-2016 are presented. Transverse single spin asymmetries from polarized p+p collisions are presented for ${\pi }^0$ and jets as a function of Feynman $x_F$. An energy scan to study the $\sqrt{s}$ dependence of collectivity and flow for small systems was performed as well as a high luminosity Au$+$Au run. The failure of a quench protection diode resulted in a pause in the run to replace it, but otherwise performance of RHIC was the best ever. Experimental results discussed are an elegant measurement from STAR of the force between anti-protons using HBT correlations, flow in U+U collisions, an improved method of generating constituent quarks by PHENIX and new Number of Quark Participants (NQP) scaling of $E_T$ distributions in p$+$p,d$+$Au and Au$+$Au which worked well. New hard-scattering results as a function of $\sqrt{s}$ in Au$+$Au central collisions are presented. Also, measurements of the di-hadron acoplanarity for ${\pi }^0+h$ and $\gamma +h$ in p+p collisions at $\sqrt{s}=500$ GeV are presented in terms of the out-of-plane transverse momentum $p_{\mathrm{out}}$ which differ from the prediction of the TMD framework of parton transverse momentum dynamics.

   nucl-ex3 citations
2. 02*

   Measurement of Meson Resonance Production in ${\pi }^{-}+$C Interactions at SPS energies

   A. Aduszkiewicz🇵🇱 · Y. Ali🇵🇱 · E.V. Andronov🇷🇺 · T. Antićić🇭🇷 · B. Baatar🇷🇺 · M. Baszczyk🇵🇱 · S. Bhosale🇵🇱 · A. Blondel🇨🇭 · M. Bogomilov🇧🇬 · A. Brandin🇷🇺 · A. Bravar🇨🇭 · J. Brzychczyk🇵🇱 and 133 other authors

   We present measurements of ${\rho }^0$, $\omega$ and K${}^{\ast 0}$ spectra in ${\pi }^{-}+$C production interactions at 158 GeV/c and ${\rho }^0$ spectra at 350 GeV/c using the NA61/SHINE spectrometer at the CERN SPS. Spectra are presented as a function of the Feynman's variable $x_{\text{F}}$ in the range $0<x_{\text{F}}<1$ and $0<x_{\text{F}}<0.5$ for 158 GeV/c and 350 GeV/c respectively. Furthermore, we show comparisons with previous measurements and predictions of several hadronic interaction models. These measurements are essential for a better understanding of hadronic shower development and for improving the modeling of cosmic ray air showers.

   nucl-exastro-ph.HEEPJC(2017)·43 citations
3. 03*

   Multiplicity Derivative: A new signature of first order phase transition in intermediate energy heavy ion collision

   S. Mallik🇮🇳 · G. Chaudhuri🇮🇳 · P. Das🇮🇳 · S Das Gupta🇨🇦

   Measurement of M, the total multiplicity, for central collision between comparable mass heavy ions can provide a signature for first order phase transition. The derivative of M with respect to E*/A where E* is the excitation energy in the centre of mass and A the total mass of the dissociating system is expected to go through maximum as a function of E*. Theoretical modelling shows that this is the energy where the specific heat Cv maximizes which typically happens at first order phase transition. The measurement of total M is probably feasible in more than one laboratory.

   ↳ nucl-thnucl-exPRC(2017)·29 citations
4. 04*

   A kinetic regime of hydrodynamic fluctuations and long time tails for a Bjorken expansion

   Yukinao Akamatsu🇯🇵 · Aleksas Mazeliauskas🇺🇸 · Derek Teaney🇺🇸

   We develop a set of kinetic equations for hydrodynamic fluctuations which are equivalent to nonlinear hydrodynamics with noise. The hydro-kinetic equations can be coupled to existing second order hydrodynamic codes to incorporate the physics of these fluctuations, which become dominant near the critical point. We use the hydro-kinetic equations to calculate the modifications of energy momentum tensor by thermal fluctuations from the earliest moments and at late times in Bjorken expansion. The solution to the kinetic equations precisely determines the coefficient of the first fractional power ($\propto {\tau }^{-3/2}$) in the energy momentum tensor gradient expansion. Numerically, we find that the contribution to the longitudinal pressure from hydrodynamic fluctuations is comparable to the second order hydrodynamic terms for typical medium parameters used to simulate heavy ion collisions.

   ↳ nucl-thhep-phnucl-exNPA(2017)·4 citations
5. 05*

   Mass differences and neutron pairing in Ca, Sn and Pb isotopes

   B.S. Ishkhanov🇷🇺 · S.V. Sidorov · T.Yu. Tretyakova · E.V. Vladimirova

   Various estimates of the even-odd effect of the mass shell of atomic nuclei are considered. Based on the experimental mass values of the Ca, Sn, and Pb isotopes, the dependence of the energy gap on the neutrons number is traced and the relationship of this characteristic to the properties of external neutron subshells is shown. In nuclei with closed proton shells, effects directly related to neutron pairing and effects of nucleon shells are discussed.

   ↳ nucl-thnucl-exCPC(2017)·4 citations
6. 06*

   An evolutionary strategy for DeltaE - E identification

   Katarzyna Schmidt🇵🇱 · Oskar Wyszynski🇵🇱

   In this article we present an automatic method for charge and mass identification of charged nuclear fragments produced in heavy ion collisions at intermediate energies. The algorithm combines a generative model of DeltaE - E relation and a Covariance Matrix Adaptation Evolutionary Strategy (CMA-ES). The CMA-ES is a stochastic and derivative-free method employed to search parameter space of the model by means of a fitness function. The article describes details of the method along with results of an application on simulated labeled data.

   ↳ physics.ins-detcs.NEnucl-exJINST(2017)·0 citations
7. 07*

   The transverse momentum distribution of hadrons within jets

   Zhong-Bo Kang🇺🇸 · Xiaohui Liu🇨🇳 · Felix Ringer🇺🇸 · Hongxi Xing🇺🇸

   We study the transverse momentum distribution of hadrons within jets, where the transverse momentum is defined with respect to the standard jet axis. We consider the case where the jet substructure measurement is performed for an inclusive jet sample $pp\to \text{jet}+X$. We demonstrate that this observable provides new opportunities to study transverse momentum dependent fragmentation functions (TMDFFs) which are currently poorly constrained from data, especially for gluons. The factorization of the cross section is obtained within Soft Collinear Effective Theory (SCET), and we show that the relevant TMDFFs are the same as for the more traditional processes semi-inclusive deep inelastic scattering (SIDIS) and electron-positron annihilation. Different than in SIDIS, the observable for the in-jet fragmentation does not depend on TMD parton distribution functions which allows for a cleaner and more direct probe of TMDFFs. We present numerical results and compare to available data from the LHC.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2017)·113 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.