Wed·Feb 7, 2018Wednesday·February 7, 2018

1. 01*

   Event plane dependence of the flow modulated background in di-hadron and jet-hadron correlations in heavy ion collisions

   Christine Nattrass🇺🇸 · Takahito Todoroki🇺🇸

   Di-hadron and jet-hadron correlations are commonly used in relativistic heavy ion collisions to study the soft component of jets in a quark gluon plasma. There is a large correlated background which is described by the Fourier decomposition of the azimuthal anisotropy where $v_n$ is the $n$th order coefficient. The path length dependence of partonic energy loss can be studied by varying the angle of the high momentum trigger particle or jet relative to a reconstructed event plane. This modifies the shape of the background correlated with that event plane. The original derivation of the shape of this background only considered correlations relative to the second order event plane, which is correlated to the initial participant plane. We derive the shape of this background for an event plane at an arbitrary order. There is a phase shift in the case of jets restricted to asymmetric regions relative to the event plane. For realistic correlations between event planes, the correlation between the second and fourth order event planes leads to a much smaller effect than the finite event plane resolution at each order. Finally, we assess the status of the rapidity even $v_1$ term due to flow, which has been measured to be comparable to $v_2$ and $v_3$ terms.

   nucl-exPRC(2018)·8 citations
2. 02*

   Photoproduction of the $\Lambda$(1405) Hyperon

   D. Werthmüller🇬🇧 · R.A. Schumacher🇺🇸

   We propose to use the high current photon beam available at A2 to produce the isosinglet $\Lambda (1405)1/2^{-}$ hyperon at threshold via $\gamma p\to K^{+}\Lambda (1405)$. Its nature is still controversial and actively debated. Since the only available photoproduction data from CLAS are lacking in precision in the ${\Sigma }^0{\pi }^0$ decay channel, we propose a new independent measurement of this most important pure $I=0$ final state including the unmeasured beam-helicity observable $I^{\odot }$. In addition, the excellent photon detection acceptance of the A2 setup will offer the opportunity for a first measurement of the radiative decays of the $\Lambda (1405)$, which will provide clean and stringent constraints for model descriptions in terms of, e.g., unitary chiral perturbation theory.

   nucl-ex0 citations
3. 03*

   Sensitivity of Proposed Search for Axion-induced Magnetic Field using Optically Pumped Magnetometers

   P.-H. Chu🇺🇸 · L. D. Duffy🇺🇸 · Y. J. Kim🇺🇸 · I. M. Savukov🇺🇸

   We investigate a search for the oscillating current induced by axion dark matter in an external magnetic field using optically pumped magnetometers (OPMs). This experiment is based upon the LC circuit axion detection concept of Sikivie, Sullivan, and Tanner. The modification of Maxwell's equations caused by the axion-photon coupling results in a minute oscillating magnetic field at the frequency equal to the axion mass in the presence of magnetic field. This induced magnetic field could be searched for using an LC circuit amplifier with an OPM, the most sensitive cryogen-free magnetic-field sensor, in a room temperature experiment, avoiding the need for a complicated and expensive cryogenic system. We discuss how an existing magnetic resonance imaging (MRI) experiment can be modified to search for axions in a previously unexplored part of the parameter space. Our existing detection setup, optimized for MRI, is already sensitive to an axion-photon coupling of $10^{-7}$ GeV${}^{-1}$ for an axion mass near $3\times 10^{-10}$ eV. While this is ruled out by limits from astrophysics and solar axion searches, we show that realistic modifications, and optimization of the experiment for axion detection, can set a new limit on the axion-photon coupling up to three orders of magnitude beyond the current best limit, for axion masses between $10^{-11}$ eV and $10^{-7}$ eV.ion masses between $10^{-11}$ eV and $10^{-7}$ eV.

   ↳ physics.ins-detnucl-exPRD(2018)·8 citations
4. 04*

   Impact of medium modification of the nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter

   Parada T. P. Hutauruk🇰🇷 · Yongseok Oh🇰🇷 · K. Tsushima🇧🇷

   Impact of the in-medium modified nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter is studied by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field model and the quark-meson coupling model are respectively adopted for the in-medium effective nucleon mass and nucleon form factors. We find that the cross sections of neutrino scattering in cold nuclear medium decreases when the in-medium modification of the nucleon weak and electromagnetic form factors are taken into account. This reduction results in the enhancement of the neutrino mean free path, in particular at the baryon density of around a few times of the normal nuclear matter density. The enhancement of the neutrino mean free path is estimated to be about 10--40\% compared with the values obtained without the medium modification of the nucleon form factors, and the enhancement is expected to accelerate the cooling of neutron stars.

   ↳ nucl-thastro-ph.HEhep-exhep-ph+1PRD(2018)·15 citations
5. 05*

   Growth and characterization of a Li2Mg2(MoO4)3 scintillating bolometer

   F.A. Danevich🇺🇦 · V.Ya. Degoda🇺🇦 · L.L. Dulger🇺🇦 · L. Dumoulin🇫🇷 · A. Giuliani🇫🇷 · P. de Marcillac🇫🇷 · S. Marnieros🇫🇷 · C. Nones🇫🇷 · V. Novati🇫🇷 · E. Olivieri🇫🇷 · A.A. Pavlyuk🇷🇺 · D.V. Poda🇺🇦 and 3 other authors

   Lithium magnesium molybdate (Li${}_2$Mg${}_2$(MoO${}_4$)${}_3$) crystals were grown by the low-thermal-gradient Czochralski method. Luminescence properties of the material (emission spectra, thermally stimulated luminescence, dependence of intensity on temperature, phosphorescence) have been studied under X-Ray excitation in the temperature interval from 8 K to 400 K, while at the same being operated as a scintillating bolometer at 20 mK for the first time. We demonstrated that Li${}_2$Mg${}_2$(MoO${}_4{)}_3$ crystals are a potentially promising detector material to search for neutrinoless double beta decay of ${}^{100}$Mo.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.(2018)·9 citations
6. 06*

   Measurement of the charged-hadron spectra and nuclear modification factor in lead--lead collisions with the ATLAS detector

   Petr Balek (for the ATLAS Collaboration)🇨🇿

   The ATLAS experiment at the Large Hadron Collider (LHC) measures charged hadron spectra obtained in 2010 and 2011 lead-lead LHC data taking periods with total integrated statistics of 0.15nb${}^{-1}$. The results are compared to the $pp$ spectra of charged hadrons at the same centre-of-mass energy based on the data sample with integrated luminosity of 4.2pb${}^{-1}$ obtained by the ATLAS experiment in 2011 and 2013. This allows a detailed comparison of the two collision systems in a wide transverse momentum ($0.5<p_{\mathrm{T}}<150$GeV) and pseudorapidity ($|\eta |<2$) ranges in different centrality intervals of Pb+Pb collision. The nuclear modification factor $R_{\mathrm{AA}}$ is presented in detail as a function of centrality, $p_{\mathrm{T}}$ and $\eta$. It shows a distinct $p_{\mathrm{T}}$-dependence with a pronounced minimum at about 7GeV. Above 60GeV, it is consistent with a flat, centrality-dependent, value within the uncertainties. The value is $0.55\pm 0.01(stat.)\pm 0.04(syst.)$ in the most central collisions. The $R_{\mathrm{AA}}$ is observed to be consistent with flat $|\eta |$ dependence over the whole transverse momentum range in all centrality classes.

   ↳ hep-exnucl-exNucl.Part.Phys.Proc.(2016)·0 citations
7. 07*

   Measurement of the nuclear modification factor for high-$p_{\mathrm{T}}$ charged hadrons in $p$+Pb collisions with the ATLAS detector

   Petr Balek (for the ATLAS Collaboration)🇮🇱

   The charged hadron spectra in $p$+Pb and $pp$ collisions at $\sqrt{s_{NN}}=\sqrt{s}=5.02$TeV are measured with the ATLAS experiment at the LHC. The measurements are performed with $p$+Pb data recorded in 2013 with an integrated luminosity of 25nb${}^{-1}$ and $pp$ data recorded in 2015 with an integrated luminosity of 28pb${}^{-1}$. The $p$+Pb results are compared to $pp$ spectra, presented as a ratio of transverse momentum distributions in the two systems scaled by the number of binary nucleon-nucleon collisions, the nuclear modification factor $R_{p\mathrm{Pb}}$. The study of $R_{\mathrm{pPb}}$ allows a detailed comparison of the collision systems in different centrality intervals and in a wide range of transverse momentum. It is shown that the nuclear modification factor does not have any significant deviation from unity in the high transverse momentum region.

   ↳ hep-exnucl-exNucl.Part.Phys.Proc.(2017)·6 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.