Tue·Nov 18, 2014Tuesday·November 18, 2014

1. 01*

   The MOLLER Experiment: An Ultra-Precise Measurement of the Weak Mixing Angle Using Møller Scattering

   MOLLER Collaboration: J. Benesch · P. Brindza · R.D. Carlini · J-P. Chen · E. Chudakov · S. Covrig · M. M. Dalton · A. Deur · D. Gaskell · A. Gavalya · J. Gomez · D. W. Higinbotham and 112 other authors

   The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Lepton Electroweak Reaction) experiment at the 12 GeV upgraded Jefferson Lab are presented. A highlight of the Fundamental Symmetries subfield of the 2007 NSAC Long Range Plan was the SLAC E158 measurement of the parity-violating asymmetry $A_{PV}$ in polarized electron-electron (Møller) scattering. The proposed MOLLER experiment will improve on this result by a factor of five, yielding the most precise measurement of the weak mixing angle at low or high energy anticipated over the next decade. This new result would be sensitive to the interference of the electromagnetic amplitude with new neutral current amplitudes as weak as $\sim 10^{-3}\cdot G_F$ from as yet undiscovered dynamics beyond the Standard Model. The resulting discovery reach is unmatched by any proposed experiment measuring a flavor- and CP-conserving process over the next decade, and yields a unique window to new physics at MeV and multi-TeV scales, complementary to direct searches at high energy colliders such as the Large Hadron Collider (LHC). The experiment takes advantage of the unique opportunity provided by the upgraded electron beam energy, luminosity, and stability at Jefferson Laboratory and the extensive experience accumulated in the community after a round of recent successfully completed parity-violating electron scattering experiments

   nucl-exhep-ph191 citations
2. 02*

   The neutron-gamma Feynman variance to mean approach: gamma detection and total neutron-gamma detection (theory and practice)

   Dina Chernikova · Kåre Axell · Senada Avdic · Imre Pázsit · Anders Nordlund

   Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have a particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with inclusion of general reactions and passage intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source enclosed in a steel container. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma, are evaluated experimentally for a weak 252Cf neutron-gamma source in a steel container, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-Y formulas.

   nucl-exnucl-thNucl.Instrum.Meth.A(2015)·2 citations
3. 03*

   Searches for Exotic Interactions Using Neutron Spin Rotation

   Chris Haddock

   Various theories beyond the Standard Model predict new particles with masses in the sub-eV range with very weak couplings to ordinary matter. I present both measured and projected limits on the strengths of two possible interactions that could be mediated by these new particles, and how one may additionally use these results to search for in matter gravitational torsion.

   nucl-ex0 citations
4. 04*

   Cross sections of deuteron induced reactions on ${}^{nat}$Sm for production of the therapeutic radionuclide ${}^{145}$Sm and ${}^{153}$Sm

   F. Tárkányi · A. Hermanne🇧🇪 · S. Takács🇭🇺 · F. Ditrói🇭🇺 · J. Csikai · A.V. Ignatyuk

   At present, targeted radiotherapy (TR) is acknowledged to have great potential in oncology. A large list of interesting radionuclides is identified, including several radioisotopes of lanthanides, amongst them ${}^{145}$Sm and ${}^{153}$Sm. In this work the possibility of their production at a cyclotron was investigated using a deuteron beam and a samarium target. The excitation functions of the ${}^{nat}$Sm(d,x)${}^{145153}$Sm reactions were determined for deuteron energies up to 50 MeV using the stacked-foil technique and high-resolution $\gamma$-ray spectrometry. The measured cross sections and the contributing reactions were analyzed by comparison with results of the ALICE, EMPIRE and TALYS nuclear reaction codes. A short overview and comparison of possible production routes is given.

   nucl-exAppl.Radiat.Isot.(2014)·1 citation
5. 05*

   Recent progress in the development of large area silica aerogel for use as RICH radiator in the Belle II experiment

   Makoto Tabata🇯🇵 · Ichiro Adachi🇯🇵 · Hideyuki Kawai🇯🇵 · Shohei Nishida🇯🇵 · Takayuki Sumiyoshi🇯🇵

   We report recent progress in the development of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter to be installed in the forward end cap of the Belle II detector, which is currently being upgraded at the High Energy Accelerator Research Organization (KEK), Japan. The production of approximately 450 aerogel tiles with refractive indices of either 1.045 or 1.055 was completed in May, 2014, and the tiles are now undergoing optical characterization. Installation of the aerogels was tested by installing them into a partial mock-up of the support structure.

   ↳ physics.ins-dethep-exnucl-exPoS(2014)·2 citations
6. 06*

   The neutron anomaly in the gamma N --> eta N cross section through the looking glass of the flavour SU(3) symmetry

   T. Boika · V. Kuznetsov🇷🇺 · M.V. Polyakov🇩🇪

   We study the implications of the flavour SU(3) symmetry for various interpretations of the neutron anomaly in the $\gamma N\to \eta N$ cross section. We show that the explanation of the neutron anomaly due to interference of known N(1535) and N(1650) resonances implies that N(1650) resonance should have a huge coupling to $\varphi$-meson -- at least 5 times larger than the corresponding ${\rho }^0$ coupling. In terms of quark degrees of freedom this means that the well-known N(1650) resonance must be a "cryptoexotic pentaquark"-- its wave function should contain predominantly an $s\bar{s}$ component. It turns out that the "conventional" interpretation of the neutron anomaly by the interference of known resonances metamorphoses into unconventional physics picture of N(1650).

   ↳ nucl-thhep-exhep-phnucl-ex5 citations
7. 07*

   Reanalysis of bubble chamber measurements of muon-neutrino induced single pion production

   Callum Wilkinson🇬🇧 · Philip Rodrigues🇺🇸 · Susan Cartwright🇬🇧 · Lee Thompson🇬🇧 · Kevin McFarland🇺🇸

   There exists a longstanding disagreement between bubble chamber measurements of the single pion production channel ${\nu }_{\mu }p\to {\mu }^{-}p{\pi }^{+}$ from the Argonne and Brookhaven National Laboratories. We digitize and reanalyse data from both experiments to produce cross-section ratios for various interaction channels, for which the flux uncertainties cancel, and find good agreement between the experiments. By multiplying the cross-section ratio by the well-understood charged current quasi-elastic cross-section on free nucleons, we extract single-pion production cross-sections which do not depend on the flux normalization predictions. The ${\nu }_{\mu }p\to {\mu }^{-}p{\pi }^{+}$ cross-sections we extract show good agreement between the ANL and BNL datasets.

   ↳ hep-exhep-phnucl-exPRD(2014)·165 citations
8. 08*

   Angular dihadron correlations as interplay of elliptic and triangular flows

   G. Eyyubova🇨🇿 · V. L. Korotkikh🇷🇺 · I. P. Lokhtin🇷🇺 · S. V. Petrushanko🇷🇺 · A. M. Snigirev🇷🇺 · L. V. Bravina🇳🇴 · E. E. Zabrodin🇳🇴

   The hybrid model HYDJET++, which combines soft and hard components, is employed for the analysis of dihadron angular correlations measured in PbPb collisions at center-of-mass energy sqrt(s_NN) = 2.76 TeV. The model allows for study both individual contributions and mutual influence of lower flow harmonics, v_2 and v_3, on higher harmonics and dihadron angular correlations. It is shown that the typical structure called ridge in dihadron angular correlations in a broad pseudorapidity range could appear just as interplay of v_2 and v_3. Central, semi-central and semi-peripheral collisions were investigated. Comparison of model results with the experimental data on dihadron angular correlations is presented for different centralities and transverse momenta p_T.

   ↳ hep-phnucl-exnucl-thPRC(2015)·33 citations
9. 09*

   Initialization of hydrodynamics in relativistic heavy ion collisions with an energy-momentum transport model

   V.Yu. Naboka🇺🇦 · S.V. Akkelin🇺🇦 · Iu.A. Karpenko🇺🇦 · Yu.M. Sinyukov🇺🇦

   A key ingredient of hydrodynamical modeling of relativistic heavy ion collisions is thermal initial conditions, an input that is the consequence of a pre-thermal dynamics which is not completely understood yet. In the paper we employ a recently developed energy-momentum transport model of the pre-thermal stage to study influence of the alternative initial states in nucleus-nucleus collisions on flow and energy density distributions of the matter at the starting time of hydrodynamics. In particular, the dependence of the results on isotropic and anisotropic initial states is analyzed. It is found that at the thermalization time the transverse flow is larger and the maximal energy density is higher for the longitudinally squeezed initial momentum distributions. The results are also sensitive to the relaxation time parameter, equation of state at the thermalization time, and transverse profile of initial energy density distribution: Gaussian approximation, Glauber Monte Carlo profiles, etc. Also, test results ensure that the numerical code based on the energy-momentum transport model is capable of providing both averaged and fluctuating initial conditions for the hydrodynamic simulations of relativistic nuclear collisions.

   ↳ nucl-thhep-phnucl-exPRC(2015)·26 citations
10. 10*

    Evidence of delayed light emission of TetraPhenyl Butadiene excited by liquid Argon scintillation light

    Ettore Segreto🇧🇷

    TetraPhenyl Butadiene is the wavelength shifter most widely used in combination with liquid Argon. The latter emits scintillation photons with a wavelength of 127 nm that need to be downshifted to be detected by photomultipliers with glass or quartz windows. TetraPhenyl Butadiene has been demonstrated to have an extremely high conversion efficiency, possibly higher than 100 % for 127 nm photons, while there is no precise information about the time dependence of its emission. It is usually assumed to be exponentially decaying with a characteristic time of the order of one ns, as an extrapolation from measurements with exciting radiation in the near UV. This work shows that TetraPhenyl Butadiene, when excited by 127 nm photons, reemits photons not only with a very short decay time, but also with slower ones due to triplet states de-excitations. This fact can strongly contribute to clarify the anomalies in liquid Argon scintillation light reported in literature since seventies, namely the inconsistency in the measured values of the long decay time constant and the appearance of an intermediate component. Similar effects should be also expected when the TPB is used in combination with Helium and Neon, that emit scintillation photons with wavelengths shorter than 127 nm.

    ↳ physics.ins-detnucl-exPRC(2015)·65 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.