Thu·Nov 10, 2016Thursday·November 10, 2016

1. 01*

   Precise measurement of the $K_{e2}/K_{\mu 2}$ branching ratio and search for new physics beyond the Standard Model

   Sébastien Bianchin (on behalf of the TREK/E36 Collaboration)🇨🇦

   The E36 experiment recently conducted at J-PARC by the TREK Collaboration will provide a precise mesurement of the decay ratio $R_K=\Gamma (K^{+}\to e^{+}{\nu }_e)/\Gamma (K^{+}\to {\mu }^{+}{\nu }_{\mu })$ with the aim of testing lepton universality, a basic assumption of the Standard Model (SM). The SM prediction for the decay ratio $R_K$ is highly precise ($\delta R_K/R_K=4\times 10^{-4}$) and any observed deviation from this prediction would clearly indicate the existence of new physics. The E36 experimental apparatus, designed to offer small systematic errors, was installed at the J-PARC K1.1BR kaon beam line in the fall of 2014, fully commissioned in the spring of 2015, and the production data were collected in the fall of 2015. A scintillating fiber target was used to stop a beam of $1.2\times 10^6{K}^{+}$ per spill. The $K^{+}$ decay products were then momentum analyzed by a 12-sector superconducting toroidal spectrometer and charged particles were tracked with high precision by Multi-Wire Proportional Chambers (MWPC) combined with a photon calorimeter with a large solid angle ($75\%$ of $4\pi$) and 3 different particle identification systems. Details of the E36 experimental apparatus, as well as the status of the data analysis will be presented.

   nucl-exJ.Phys.Conf.Ser.(2017)·3 citations
2. 02*

   Measurement of the ${}^{232}$Th (n, $\gamma$ )/${}^{58}$Ni (n, p) reaction rate ratio in the leakage neutron field of CFBR-II fast burst reactor

   Qiang Wang · Li-Na Zeng · Zi-Hui Ai · Chun Zheng · Jian Gong

   A ThO${}_2$ sample and a nickel activation foil were irradiated in the leakage neutron field of CFBR-II reactor. The activities of the activation products were measured after irradiation to obtain the reaction rates. The normalized reaction rates were also calculated based on the ENDF/B-VII.1, CENDL-3.1, JENDL-4.0, BROND-2.2 databases. The experimental reaction rate ratio is 4.37 with an uncertainty of 3.9\% which is coincident with each of the ratios calculated based on the ENDFB-VII. 1, JENDL-4.0, BROND-2.2 databases, but is 11.2\% larger than that based on CENDL-3.1 database.

   nucl-ex0 citations
3. 03*

   Tagging fast neutrons from a 252Cf fission-fragment source

   Julius Scherzinger · Ramsey Al Jebali · John Annand · Kevin Fissum · Richard Hall-Wilton · Nicholai Mauritzson · Francesco Messi · Hanno Perrey · Emil Rofors

   Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a 252Cf source sealed on one side with a very thin layer of Au. The source is positioned within a gaseous 4He scintillator detector. Together with alpha particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fission neutrons, which are detected in a NE-213 liquid-scintillator detector, to be tagged. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations. We anticipate that this technique will provide a cost-effective means for the characterization of neutron-detector efficiency in the energy range 1 - 6 MeV.

   nucl-exAppl.Radiat.Isot.(2017)·7 citations
4. 04*

   Measurement of excitation spectra in the ${}^{12}$C$(p,d)$ reaction near the ${\eta }^{\prime }$ emission threshold

   Y. K. Tanaka🇯🇵 · K. Itahashi🇯🇵 · H. Fujioka🇯🇵 · Y. Ayyad🇯🇵 · J. Benlliure🇪🇸 · K.-T. Brinkmann🇩🇪 · S. Friedrich🇩🇪 · H. Geissel🇩🇪 · J. Gellanki🇳🇱 · C. Guo🇨🇳 · E. Gutz🇩🇪 · E. Haettner🇩🇪 and 42 other authors

   Excitation spectra of ${}^{11}$C were measured in the ${}^{12}$C$(p,d)$ reaction near the ${\eta }^{\prime }$ emission threshold. A proton beam extracted from the synchrotron SIS-18 at GSI with an incident energy of 2.5 GeV impinged on a carbon target. The momenta of deuterons emitted at 0 degrees were precisely measured with the fragment separator FRS operated as a spectrometer. In contrast to theoretical predictions on the possible existence of deeply bound ${\eta }^{\prime }$ mesic states in carbon nuclei, no distinct structures were observed associated with the formation of bound states. The spectra were analyzed to set stringent constraints on the formation cross section and on the hitherto barely-known ${\eta }^{\prime }$-nucleus interaction.

   nucl-exPRL(2016)·69 citations
5. 05*

   W and Z boson production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

   Alice Collaboration

   The W and Z boson production was measured via the muonic decay channel in proton-lead collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV at the Large Hadron Collider with the ALICE detector. The measurement covers backward ($-4.46<y_{\mathrm{cms}}<-2.96$) and forward ($2.03<y_{\mathrm{cms}}<3.53$) rapidity regions, corresponding to Pb-going and p-going directions, respectively. The Z-boson production cross section, with dimuon invariant mass of $60<m_{\mu \mu }<120$ GeV/$c^2$ and muon transverse momentum ($p_{\mathrm{T}}^{\mu }$) larger than 20 GeV/$c$, is measured. The production cross section and charge asymmetry of muons from W-boson decays with $p_{\mathrm{T}}^{\mu }>10$ GeV/$c$ are determined. The results are compared to theoretical calculations both with and without including the nuclear modification of the parton distribution functions. The W-boson production is also studied as a function of the collision centrality: the cross section of muons from W-boson decays is found to scale with the average number of binary nucleon-nucleon collisions within uncertainties.

   nucl-exhep-exJHEP(2017)·68 citations
6. 06*

   sPHENIX: The next generation heavy ion detector at RHIC

   Sarah Campbell (for the sPHENIX Collaboration)🇺🇸

   sPHENIX is a new collaboration and future detector project at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC). It seeks to answer fundamental questions on the nature of the quark gluon plasma (QGP), including its temperature dependence and coupling strength, by using a suite of precision jet and upsilon measurements that probe different length scales of the QGP. This will be achieved with large acceptance, $|\eta |<1$ and $0$-$2\pi$ in $\varphi$, electromagentic and hadronic calorimeters and precision tracking enabled by a $1.5$ T superconducting magnet. With the increased luminosity afforded by accelerator upgrades, sPHENIX will perform high statistics measurements extending the kinematic reach at RHIC to overlap the LHC's. This overlap with the LHC will facilitate better understanding of the role of temperature, density and parton virtuality in QGP dynamics and for jet quenching in particular. This talk will focus on key future measurements and the current state of the sPHENIX project.

   ↳ physics.ins-detnucl-exJ.Phys.Conf.Ser.(2017)·13 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.