Mon·Oct 5, 2015Monday·October 5, 2015

1. 01*

   Collectivity in Small QCD Systems

   Theodore Koblesky🇺🇸

   Features of collectivity observed in high energy A+A collision systems at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) imply a strongly coupled quark gluon plasma (QGP) that flows. One defining feature of collectivity is long-range angular correlations which are characterized experimentally by measuring the azimuthal anisotropy of particles well separated in rapidity. Evidence indicating long-range angular correlations include the appearance of the so-called near-side "ridge" in correlation functions and $p_T$ dependent flow components ($v_N$). These features have been well measured at RHIC for Au+Au collisions at $\sqrt{s_{NN}}$= 200 GeV and at the LHC for Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. However, evidence of collectivity has recently been observed at the LHC in p+p high multiplicity collisions at $\sqrt{s_{NN}}$ = 7.0 TeV and p+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV and then at RHIC in d+Au and $3^{H}e$+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. In this talk, we present the recent PHENIX results for d+Au and ${}^{3}He$+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. Precise measurements of anisotropy help distinguish between theoretical models based on relativistic hydrodynamics or Color Glass Condensate (CGC). Comparisons of these measurements to various theoretical models are shown.

   nucl-ex1 citation
2. 02*

   First Measurement of the Beam Normal Single Spin Asymmetry in $\Delta$ Resonance Production by $Q_{\mathrm{weak}}$

   Nuruzzaman (for the Q_weak Collaboration)🇺🇸

   The beam normal single spin asymmetry ($B_{\mathrm{n}}$) is generated in the scattering of transversely polarized electrons from unpolarized nuclei. The asymmetry arises from the interference of the imaginary part of the two-photon exchange with the one-photon exchange amplitude. The $Q_{\mathrm{weak}}$ experiment has made the first measurement of $B_{\mathrm{n}}$ in the production of the $\Delta$(1232) resonance, using the $Q_{\mathrm{weak}}$ apparatus in Hall-C at the Thomas Jefferson National Accelerator Facility. The final transverse asymmetry, corrected for backgrounds and beam polarization, is $B_{\mathrm{n}}$ = 43 $\pm$ 16 ppm at beam energy 1.16 GeV at an average scattering angle of about 8.3 degrees, and invariant mass of 1.2 GeV. The measured preliminary $B_{\mathrm{n}}$ agrees with a preliminary theoretical calculation. $B_{\mathrm{n}}$ for the $\Delta$ is the only known observable that is sensitive to the $\Delta$ elastic form-factors ($\gamma$*$\Delta \Delta$) in addition to the generally studied transition form-factors ($\gamma$*N$\Delta$), but extracting this information will require significant theoretical input.

   nucl-ex8 citations
3. 03*

   Soft photon registration at Nuclotron

   Elena Kokoulina🇷🇺 · E. Ardashev🇷🇺 · V. Golovkin🇷🇺 · S. Golovnya🇷🇺 · S. Gorokhov🇷🇺 · A. Kholodenko🇷🇺 · A. Kiryakov🇷🇺 · I. Lobanov🇷🇺 · M. Polkovnikov🇷🇺 · V. Ronzhin🇷🇺 · V. Ryadovikov🇷🇺 · Yu. Tsyupa🇷🇺 and 21 other authors

   First results of a soft photon yield in nucleus-nuclear interactions at 3.5 GeV per nucleon are presented. These photons have been registered at Nuclotron (LHEP, JINR) by an electromagnetic calorimeter built in the SVD Collaboration. The obtained spectra confirm the excess yield in the energy region less than 50 MeV in comparison with theoretical predictions and agree with previous experiments at high-energy interactions.

   nucl-exPoS(2016)·1 citation
4. 04*

   Production of Quarkonia at RHIC

   Robert Vertesi🇨🇿

   The production of different quarkonium states provides unique insight to the hot and cold nuclear matter effects in the strongly interacting medium that is formed in high energy heavy ion collisions. While LHC explores the energy frontier, RHIC has a broad physics program to explore the nuclear modification at different energies in a wide range of systems. Some of the most interesting recent results on $J/\psi$ and ${\rm Y}$ production in p+p, d+Au and A+A collisions from PHENIX and STAR are summarized in this work.

   nucl-exInt.J.Mod.Phys.A(2016)·1 citation
5. 05*

   A Future Polarized Drell-Yan Experiment at Fermilab

   David Kleinjan🇺🇸

   One of the great challenges of QCD is trying to understand the origin of the nucleon spin. Several decades of experimental measurements have shown that our current understanding is incomplete if only the quark and gluon spin contribution is considered. Over the last few years it has become increasingly clear that the contribution from the orbital angular momentum of the quarks and gluons has to be included as well. For instance, the sea quark orbital contribution remains largely unexplored. Measurements accessing the sea quark Sivers distribution will provide a probe of the sea quark orbital contribution. The upcoming E1039 experiment at Fermilab will access this distribution via the Drell-Yan process using a 120 GeV unpolarized proton beam directed on a polarized proton target. At E1039 kinematics the $u$-$\bar{u}$ annihilation process dominates the Drell-Yan cross section ($x_{Target}$ = 0.1 $\sim$ 0.35). If the $\bar{u}$ quark carries zero net angular momentum, then the measured Drell-Yan single-spin asymmetry should be zero, and vice versa. This experiment is a continuation of the currently running SeaQuest experiment.

   nucl-exhep-exhep-ph0 citations
6. 06*

   Muon g-2 Experiment at Fermilab

   Frederick Gray (for the Fermilab E989 Muon g-2 Collaboration)🇺🇸

   A new experiment at Fermilab will measure the anomalous magnetic moment of the muon with a precision of 140 parts per billion (ppb). This measurement is motivated by the results of the Brookhaven E821 experiment that were first released more than a decade ago, which reached a precision of 540 ppb. As the corresponding Standard Model predictions have been refined, the experimental and theoretical values have persistently differed by about 3 standard deviations. If the Brookhaven result is confirmed at Fermilab with this improved precision, it will constitute definitive evidence for physics beyond the Standard Model. The experiment observes the muon spin precession frequency in flight in a well-calibrated magnetic field; the improvement in precision will require both 20 times as many recorded muon decay events as in E821 and a reduction by a factor of 3 in the systematic uncertainties. This paper describes the current experimental status as well as the plans for the upgraded magnet, detector and storage ring systems that are being prepared for the start of beam data collection in 2017.

   ↳ physics.ins-dethep-exnucl-ex12 citations
7. 07*

   Dilepton emission in high-energy heavy-ion collisions with dissipative hydrodynamics

   Gojko Vujanovic🇨🇦 · Gabriel S. Denicol🇨🇦 · Chun Shen🇨🇦 · Matthew Luzum🇨🇦 · Bjoern Schenke🇺🇸 · Sangyoung Jeon🇨🇦 · Charles Gale🇨🇦

   In this contribution we study the effects of three transport coefficients of dissipative hydrodynamics on thermal dilepton anisotropic flow observables. The first two transport coefficients investigated influence the overall size and growth rate of shear viscous pressure, while the last transport coefficient governs the magnitude of net baryon number diffusion in relativistic dissipative fluid dynamics. All calculations are done using state-of-the-art 3+1D hydrodynamical simulations. We show that thermal dileptons are sensitive probes of the transport coefficients of dissipative hydrodynamics.

   ↳ nucl-thhep-phnucl-ex3 citations
8. 08*

   Properties of hot and dense matter from relativistic heavy ion collisions

   Peter Braun-Munzinger🇩🇪 · Volker Koch🇺🇸 · Thomas Schaefer🇺🇸 · Johanna Stachel🇩🇪

   We review the progress achieved in extracting the properties of hot and dense matter from relativistic heavy ion collisions at the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory and the large hadron collider (LHC) at CERN. We focus on bulk properties of the medium, in particular the evidence for thermalization, aspects of the equation of state, transport properties, as well as fluctuations and correlations. We also discuss the in-medium properties of hadrons with light and heavy quarks, and measurements of dileptons and quarkonia. This review is dedicated to the memory of Gerald E. Brown.

   ↳ nucl-thhep-phnucl-exPhys.Rept.(2016)·385 citations
9. 09*

   Measurement of $\alpha$-particle quenching in LAB based scintillator in independent small-scale experiments

   B. von Krosigk🇨🇦 · M. Chen🇨🇦 · S. Hans🇺🇸 · A.R. Junghans🇩🇪 · T. Kögler🇩🇪 · C. Kraus🇨🇦 · L. Kuckert🇩🇪 · X. Liu🇨🇦 · R. Nolte🇩🇪 · H.M. O'Keeffe🇬🇧 · H.S. Wan Chan Tseung🇺🇸 · J.R. Wilson🇬🇧 and 3 other authors

   The $\alpha$-particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, $\alpha$-particles were produced in the scintillator via ${}^{12}$C($n$,$\alpha$)${}^9$Be reactions. In the second approach, the scintillator was loaded with 2% of ${}^{\mathrm{nat}}$Sm providing an $\alpha$-emitter, ${}^{147}$Sm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants ${}^{222}$Rn, ${}^{218}$Po and ${}^{214}$Po provided the $\alpha$-particle signal. The behavior of the observed $\alpha$-particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter $kB$ ranges from $(0.0066\pm 0.0016)$ cm/MeV to $(0.0076\pm 0.0003)$ cm/MeV. In the first approach, the $\alpha$-particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proton elastic scattering. This enabled a first time a direct comparison of $kB$ describing the proton and the $\alpha$-particle response of LAB based scintillator. The observed $kB$ values describing the two light response functions deviate by more than $5\sigma$. The presented results are valuable for all current and future detectors, using LAB based scintillator as target, since they depend on an accurate knowledge of the scintillator response to different particles.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-exEPJC(2016)·20 citations
10. 10*

    Non-perturbative collisional energy loss of heavy quarks in quark-gluon plasma

    Nikolai Kochelev🇷🇺 · Hee-Jung Lee🇰🇷 · Yongseok Oh🇰🇷 · Baiyang Zhang🇨🇳 · Pengming Zhang🇨🇳

    We suggest a new mechanism for the energy loss of fast heavy quarks in quark-gluon plasma. This mechanism is based on pion production caused by the anomalous chromomagnetic quark-gluon-pion interaction induced by strong topological fluctuations of the gluon fields represented by instantons. We found that this mechanism gives a considerable contribution to the collisional energy loss of a heavy quark in quark-gluon plasma, which shows a nontrivial role of nonperturbative phenomena in strongly interacting quark-gluon plasma.

    ↳ hep-phhep-exnucl-exnucl-thPRC(2016)·5 citations
11. 11*

    Electron capture rates in stars studied with heavy ion charge exchange reactions

    C.A. Bertulani🇺🇸

    Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean $\sim$ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.

    ↳ nucl-thastro-ph.SRnucl-exJ.Phys.Conf.Ser.(2018)·1 citation
12. 12*

    Determination of shower central position in laterally segmented lead-fluoride electromagnetic calorimeters

    M. Mazouz🇹🇳 · L. Ghedira🇹🇳 · E. Voutier🇫🇷

    The spatial resolution of laterally segmented electromagnetic calorimeters is studied on the basis of Monte-Carlo simulations worked-out for lead fluoride material. Parametrization of the relative resolution is proposed and optimized in terms of the energy of incoming particles and the elementary size of the calorimeter blocks. A new fit algorithm method is proposed that improves spatial resolution at high energies, and provides guidance for the design optimization of electromagnetic calorimeters.

    ↳ physics.ins-dethep-exnucl-exJINST(2016)·7 citations
13. 13*

    Measurement of the $e^{+}{e}^{-}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ cross section with the CMD-3 detector at the VEPP-2000 collider

    D.N. Shemyakin🇷🇺 · G.V. Fedotovich🇷🇺 · R.R. Akhmetshin🇷🇺 · A.N. Amirkhanov🇷🇺 · A.V. Anisenkov🇷🇺 · V.M. Aulchenko🇷🇺 · V.Sh. Banzarov🇷🇺 · N.S. Bashtovoy🇷🇺 · A.E. Bondar🇷🇺 · A.V. Bragin🇷🇺 · S.I. Eidelman🇷🇺 · D.A. Epifanov🇯🇵 and 42 other authors

    The process $e^{+}{e}^{-}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ has been studied in the center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23 pb${}^{-1}$ collected with the CMD-3 detector at the VEPP-2000 $e^{+}{e}^{-}$ collider. Using about 24000 selected events, the $e^{+}{e}^{-}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ cross section has been measured with a systematic uncertainty decreasing from 11.7\% at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of $K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ production dynamics has been performed.

    ↳ hep-exnucl-exPLB(2016)·58 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.