Tue·Nov 3, 2015Tuesday·November 3, 2015

1. 01*

   Parton Dynamics at PHENIX

   J.D. Osborn🇺🇸

   Investigating partonic interactions is one of the primary goals of the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). RHIC is specially tailored for studying intrinsic partonic spin-momentum correlations due to its unique ability to collide polarized proton beams. Transverse single-spin asymmetries of order 10% have been measured in PHENIX at center of mass energies from 62.4 GeV to 200 GeV, similar to previous measurements. These results indicate that there exist partonic transverse momentum effects within the proton and/or within the process of hadronization. The MPC-EX, a new silicon-tungsten preshower detector at PHENIX, has taken data for the first time this year with the intent of shedding further light on the origins of these asymmetries. A review of the status of the detector and of future planned measurements will be presented. An overview of ongoing work by PHENIX aimed at measuring intrinsic partonic transverse momentum will be discussed.

   nucl-ex0 citations
2. 02*

   Measurement of two particle pseudorapidity correlations in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV with the ATLAS detector

   Sooraj Radhakrishnan (for the ATLAS Collaboration)🇺🇸

   Two-particle pseudorapidity correlations, measured using charged particles with $p_{\mathrm{T}}>$ 0.5 GeV and $|\eta |<$ 2.4, from $\sqrt{s_{NN}}$ = 2.76 TeV Pb+Pb collisions collected in 2010 by the ATLAS experiment at the LHC are presented. The correlation function $C_N({\eta }_1,{\eta }_2)$ is measured for different centrality intervals as a function of the pseudorapidity of the two particles, ${\eta }_1$ and ${\eta }_2$. The correlation function shows an enhancement along ${\eta }_{-}\equiv {\eta }_1-{\eta }_2\approx$ 0 and a suppression at large ${\eta }_{-}$ values. The correlation function also shows a quadratic dependence along the ${\eta }_{+}\equiv {\eta }_1$ + ${\eta }_2$ direction. These structures are consistent with a strong forward-backward asymmetry of the particle multiplicity that fluctuates event to event. The correlation function is expanded in an orthonormal basis of Legendre polynomials, $T_n({\eta }_1)T_m({\eta }_2)$, and corresponding coefficients $a_{n,m}$ are measured. These coefficients are related to mean-square values of the Legendre coefficients, $a_n$, of the single particle longitudinal multiplicity fluctuations: $a_{n,m}=⟨a_n{a}_m⟩$. Significant values are observed for the diagonal terms $⟨a_n^2⟩$ and mixed terms $⟨a_n{a}_{n+2}⟩$. Magnitude of $⟨a_1^2⟩$ is the largest and the higher order terms decrease quickly with increase in $n$. The centrality dependence of the leading coefficient $⟨a_1^2⟩$ is compared to that of the mean-square value of the asymmetry of the number of participating nucleons between the two colliding nuclei, and also to the $⟨a_1^2⟩$ calculated from HIJING.

   nucl-exNucl.Part.Phys.Proc.(2016)·4 citations
3. 03*

   Validity of the generalized Brink-Axel hypothesis in ${}^{238}$Np

   M. Guttormsen🇳🇴 · A.C. Larsen🇳🇴 · A. Görgen🇳🇴 · T. Renstrøm🇳🇴 · S. Siem🇳🇴 · T.G. Tornyi🇳🇴 · G.M. Tveten🇳🇴

   We have analyzed primary $\gamma$-ray spectra of the odd-odd ${}^{238}$Np nucleus extracted from ${}^{237}$Np($d,p\gamma$)${}^{238}$Np coincidence data measured at the Oslo Cyclotron Laboratory. The primary $\gamma$ spectra cover an excitation-energy region of $0\le E_i\le 5.4$ MeV, and allowed us to perform a detailed study of the $\gamma$-ray strength as function of excitation energy. Hence, we could test the validity of the generalized Brink-Axel hypothesis, which, in its strictest form, claims no excitation-energy dependence on the $\gamma$ strength. In this work, using the available high-quality ${}^{238}$Np data, we show that the $\gamma$-ray strength function is to a very large extent independent on the initial and final states. Thus, for the first time, the generalized Brink-Axel hypothesis has been experimentally verified for $\gamma$ transitions between states in the quasi-continuum region, not only for specific collective resonances, but also for the full strength below the neutron separation energy. Based on our findings, the necessary criteria for the generalized Brink-Axel hypothesis to be fulfilled are outlined.

   nucl-exnucl-thPRL(2016)·67 citations
4. 04*

   Solution of the proton radius puzzle? Low momentum transfer electron scattering data are not enough

   Michael O. Distler🇩🇪 · Thomas Walcher🇩🇪 · Jan C. Bernauer🇺🇸

   In two recent papers it is argued that the 'proton radius puzzle' can be explained by truncating the electron scattering data to low momentum transfer and fit the rms radius in the low momentum expansion of the form factor. It is shown that this procedure is inconsistent and violates the Fourier theorem. The puzzle cannot be explained in this way.

   nucl-exnucl-th13 citations
5. 05*

   Light-quark baryon spectroscopy from ANL-Osaka dynamical coupled-channels analysis

   Hiroyuki Kamano🇯🇵

   We review our recent efforts for determining resonance parameters associated with light-quark baryons ($N^{\ast }$, ${\Delta }^{\ast }$, ${\Lambda }^{\ast }$, ${\Sigma }^{\ast }$) through comprehensive analyses of various meson production reactions off the nucleon within the ANL-Osaka dynamical coupled-channels approach.

   ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2016)·1 citation
6. 06*

   Photon and neutral pion production in pp and Pb-Pb collisions at LHC energies in the ALICE experiment

   Podist Kurashvili (for the ALICE Collaboration)🇵🇱

   We present the results for direct photon and neutral pion production obtained from proton-proton and lead-lead collisions in the ALICE experiment. Measurement of neutral pions in pp collisions allows to test the validity of QCD-inspired models. The study of neutral pion yields in Pb-Pb collisions permits to study the medium-induced suppression relative to the pp case. The yield of direct photons is compared to perturbative QCD calculations. In the case of central Pb-Pb collisions the observed excess of photons below 4 GeV/c is used to find the effective temperature of the matter.

   ↳ hep-exnucl-ex0 citations
7. 07*

   Status Update of the MAJORANA DEMONSTRATOR Neutrinoless Double Beta Decay Experiment

   Julieta Gruszko🇺🇸 · Nicolas Abgrall🇺🇸 · Isaac Arnquist🇺🇸 · Frank Avignone III🇺🇸 · Alexander Barabash🇷🇺 · Fred Bertrand🇺🇸 · Adam Bradley🇺🇸 · Viktor Brudanin🇷🇺 · Matthew Busch🇺🇸 · Micah Buuck🇺🇸 · Dana Byram🇺🇸 · Adam Caldwell🇺🇸 and 58 other authors

   Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The \textsc{Majorana} Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in ${}^{76}$Ge. The \textsc{Majorana Demonstrator}, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in ${}^{76}$Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

   ↳ physics.ins-detnucl-ex1 citation
8. 08*

   On the measurement of Adler angles in charge current single pion neutrino-nucleusinteractions

   F. Sánchez🇪🇸

   The modelling of neutrino nucleus interactions is one of the limiting systematic errors in long base line neutrino oscillation experiments. The accurate modelling of the neutrino interactions requires more experimental observables to determine its accuracy. Adler Angles are observables carrying information about the polarization of the ?{\Delta} resonance and the interference with the non-resonant single pion production. These observables were measured with limited statistics in bubble chamber experiments. We discuss the possibility of measuring the angles in neutrino interactions with nucleus.

   ↳ hep-exhep-phnucl-exPRD(2016)·14 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.