Mon·Jan 22, 2018Monday·January 22, 2018

1. 01*

   Measurement of $\hat{q}$ in RHI collisions using di-hadron correlations

   M. J. Tannenbaum🇺🇸

   In the BDMPSZ model, the energy loss of an outgoing parton in a medium $-dE/dx$ is the transport coefficient $\hat{q}$ times $L$ the length traveled. This results in jet quenching, which is well established. However BDMPSZ also predicts an azimuthal broadening of di-jets also proportional to $\hat{q}L$ which has so far not been observed. The broadening should produce a larger $k_T$ in A$+$A than in p$+$p collisions. This presentation introduces the observation that the $k_T$ measured in p$+$p collisions for di-hadrons with $p_{Tt}$ and $p_{Ta}$ must be reduced to compensate for the energy loss of both the trigger and away parent partons when comparing to the $k_T$ measured with the same di-hadron $p_{Tt}$ and $p_{Ta}$ in A$+$A collisions. This idea is applied to a recent STAR di-hadron measurement in Au$+$Au at $\sqrt{s_{NN}}$=200 GeV, [Phys. Lett. B760 (2016) 689], with result $<\hat{q}L>=2.1\pm 0.6$ GeV${}^2$. This is more precise but in agreement with a theoretical calculation of $<\hat{q}L>=14_{-14}^{+42}$ GeV${}^2$ using the same data. Assuming a length $<L>\approx 7$ fm for central Au$+$Au collisions the present result gives $\hat{q}\approx 0.30\pm 0.09$ GeV${}^2$/fm, in fair agreement with the JET collaboration result from single hadron suppression of $\hat{q}\approx 1.2\pm 0.3$ GeV${}^2$/fm at an initial time ${\tau }_0=0.6$ fm/c in Au$+$Au collisions at $\sqrt{s_{NN}}=200$ GeV. There are several interesting details to be discussed: for a given $p_{Tt}$ the $<\hat{q}L>$ seems to decrease then vanish with increasing $p_{Ta}$; the di-jet spends a much longer time in the medium ($\approx 7$ fm/c) then ${\tau }_0=0.6$ fm/c which likely affects the value of $\hat{q}$ that would be observed.

   nucl-exPoS(2019)·0 citations
2. 02*

   Hadron tomography and its application to gravitational radii of hadrons

   S. Kumano🇯🇵 · Qin-Tao Song🇯🇵 · O. V. Teryaev🇷🇺

   Hadron tomography has been investigated by three-dimensional structure functions, such as generalized parton distributions (GPDs) and generalized distribution amplitudes (GDAs). The GDAs are $s$-$t$ crossed quantities of the GPDs, and both functions probe gravitational form factors for hadrons. We determined the pion GDAs by analyzing Belle data on the differential cross section for the two-photon process ${\gamma }^{\ast }\gamma \to {\pi }^0{\pi }^0$. From the determined GDAs, we calculated timelike gravitational form factors of the pion and they were converted to the spacelike form factors by using the dispersion relation. These gravitational form factors ${\Theta }_1$ and ${\Theta }_2$ indicate mechanical (pressure, shear force) and gravitational-mass (or energy) distributions, respectively. Then, gravitational radii are calculated for the pion from the form factors, and they are compared with the pion charge radius. We explain that the new field of gravitational physics can be developed in the microscopic level of quarks and gluons.

   ↳ hep-phhep-exhep-latnucl-ex+1Few Body Syst.(2018)·2 citations
3. 03*

   Status and Prospects of the Search for Neutrinoless Double Beta Decay of ${}^{76}$Ge

   Karl-Tasso Knoepfle (for the GERDA collaboration)🇩🇪

   This paper presents a review of the search for neutrinoless double beta decay of ${}^{76}$Ge with emphasis on the recent results of the GERDA experiment. It includes an appraisal of fifty years of research on this topic as well as an outlook.

   ↳ hep-exnucl-exphysics.ins-detProc. 18th Lomonosov Conference on Elemen…·0 citations
4. 04*

   Model-Independent ${\bar{\nu }}_e$ Short-Baseline Oscillations from Reactor Spectral Ratios

   S. Gariazzo🇪🇸 · C. Giunti🇮🇹 · M. Laveder🇮🇹 · Y.F. Li🇨🇳

   We consider the ratio of the spectra measured in the DANSS neutrino experiment at 12.7 and 10.7~m from a nuclear reactor. These data give a new model-independent indication in favor of short-baseline ${\bar{\nu }}_e$ oscillations which reinforce the model-independent indication found in the late 2016 in the NEOS experiment. The combined analysis of the NEOS and DANSS spectral ratios in the framework of 3+1 active-sterile neutrino mixing favor short-baseline ${\bar{\nu }}_e$ oscillations with a statistical significance of $3.7\sigma$. The two mixing parameters ${\sin }^{2}2{\vartheta }_{ee}$ and $\Delta m_{41}^2$ are constrained at $2\sigma$ in a narrow-$\Delta m_{41}^2$ island at $\Delta m_{41}^2\simeq 1.3{\text{eV}}^2$, with ${\sin }^{2}2{\vartheta }_{ee}=0.049\pm 0.023$ ($2\sigma$). We discuss the implications of the model-independent NEOS+DANSS analysis for the reactor and Gallium anomalies. The NEOS+DANSS model-independent determination of short-baseline ${\bar{\nu }}_e$ oscillations allows us to analyze the reactor rates without assumptions on the values of the main reactor antineutrino fluxes and the data of the Gallium source experiments with free detector efficiencies. The corrections to the reactor neutrino fluxes and the Gallium detector efficiencies are obtained from the fit of the data. In particular, we confirm the indication in favor of the need for a recalculation of the ${}^{235}\text{U}$ reactor antineutrino flux found in previous studies assuming the absence of neutrino oscillations.

   ↳ hep-phhep-exnucl-exPLB(2018)·90 citations
5. 05*

   Investigating Local Parity Violation in Heavy-Ion Collisions Using Lambda Helicity

   L. Evan Finch🇺🇸 · Stephen J. Murray🇺🇸

   We propose the measurement of net $\Lambda$ and $\bar{\Lambda }$ helicity, correlated event-by-event with the magnitude and sign of charge separation along the event's magnetic field direction, as a probe to investigate the Chiral Magnetic Effect in Heavy-Ion Collisions. With a simple simulation model of heavy-ion events that includes effects of Local Parity Violation, we estimate the experimental correlation signal that could be expected at RHIC given the results of previous measurements that are sensitive to the CME.

   ↳ hep-phnucl-exPRC(2017)·11 citations
6. 06*

   The Soreq Applied Research Accelerator Facility (SARAF) - Overview, Research Programs and Future Plans

   Israel Mardor (1,2)🇮🇱 · Ofer Aviv (2)🇮🇱 · Marilena Avrigeanu (3)🇷🇴 · Dan Berkovits (2)🇮🇱 · Adi Dahan (2)🇮🇱 · Timo Dickel (4,5)🇩🇪 · Ilan Eliyahu (2)🇮🇱 · Moshe Gai (6)🇺🇸 · Inbal Gavish-Segev (2)🇮🇱 · Shlomi Halfon (2)🇮🇱 · Michael Hass (7)🇮🇱 · Tsviki Hirsh (2)🇮🇱 and 17 other authors

   The Soreq Applied Research Accelerator Facility (SARAF) is under construction in the Soreq Nuclear Research Center at Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility for basic and applied nuclear physics, based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (SARAF-I, 4 MeV, 2 mA CW protons, 5 MeV 1 mA CW deuterons) is already in operation, generating scientific results in several fields of interest. The main ongoing program at SARAF-I is the production of 30 keV neutrons and measurement of Maxwellian Averaged Cross Sections (MACS), important for the astrophysical s-process. The world leading Maxwellian epithermal neutron yield at SARAF-I ($5\times 10^{10}$ epithermal neutrons/sec), generated by a novel Liquid-Lithium Target (LiLiT), enables improved precision of known MACSs, and new measurements of low-abundance and radioactive isotopes. Research plans for SARAF-II span several disciplines: Precision studies of beyond-Standard-Model effects by trapping light exotic radioisotopes, such as ${}^6$He, ${}^8$Li and ${}^{18,19,23}$Ne, in unprecedented amounts (including meaningful studies already at SARAF-I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; nuclear structure of exotic isotopes; high energy neutron cross sections for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radiopharmaceuticals development and production. In this paper we present a technical overview of SARAF-I and II, including a description of the accelerator and its irradiation targets; a survey of existing research programs at SARAF-I; and the research potential at the completed facility (SARAF-II).

   ↳ physics.ins-detnucl-exEPJA(2018)·66 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.