Fri·Jul 11, 2014Friday·July 11, 2014

1. 01*

   Charge Symmetry Breaking in dd->4He{\pi}0 with WASA-at-COSY

   WASA-at-COSY Collaboration: P. Adlarson🇸🇪 · W. Augustyniak🇵🇱 · W. Bardan🇵🇱 · M. Bashkanov🇩🇪 · F.S. Bergmann🇩🇪 · M. Berłowski🇵🇱 · H. Bhatt🇮🇳 · A. Bondar🇷🇺 · M. Büscher🇩🇪 · H. Calén🇸🇪 · I. Ciepał🇵🇱 · H. Clement🇩🇪 and 92 other authors

   Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In this work the experimental studies on the reaction dd->4He{\pi}0 have been extended towards higher excess energies in order to provide information on the contribution of p-waves in the final state. For this, an exclusive measurement has been carried out at a beam momentum of p=1.2 GeV/c using the WASA-at-COSY facility. The total cross section amounts to sigma(tot) = (118 +- 18(stat) +- 13(sys) +- 8(ext)) pb and first data on the differential cross section are consistent with s-wave pion production.

   nucl-exPLB(2014)·14 citations
2. 02*

   Multiple chiral doublet bands of identical configuration in 103Rh

   I. Kuti🇭🇺 · Q. B. Chen🇨🇳 · J. Timar🇭🇺 · D. Sohler🇭🇺 · S. Q. Zhang · Z. H. Zhang · P. W. Zhao🇨🇳 · J. Meng🇨🇳 · K. Starosta · T. Koike🇯🇵 · E. S. Paul🇩🇪 · D. B. Fossan · C. Vaman

   Three sets of chiral doublet band structures have been identified in the 103Rh nucleus. The properties of the observed chiral doublet bands are in good agreement with theoretical results obtained using constrained covariant density functional theory and particle rotor model calculations. Two of them belong to an identical configuration, and provide the first experimental evidence for a novel type of multiple chiral doublets, where an "excited" chiral doublet of a configuration is seen together with the "yrast" one. This observation shows that the chiral geometry in nuclei can be robust against the increase of the intrinsic excitation energy.

   nucl-exnucl-thPRL(2014)·103 citations
3. 03*

   Beam Energy Dependence of Clan Multiplicity at RHIC

   Aihong Tang (for the STAR Collaboration)🇺🇸

   In this paper, STAR's measurement of clan multiplicity is presented for AuAu collisions at $\sqrt{s_{\mathrm{NN}}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV, for a variety of centrality classes. The mean number of particles per clan is found to decrease with decreasing centrality. Within the same centrality class, the mean number of particles per clan exhibits a reduction between 19.6 GeV and 62 GeV, with the minimum around 27 GeV. The structure is visible for most centralities, and most prominent for central collisions.

   nucl-exnucl-thJ.Phys.Conf.Ser.(2014)·2 citations
4. 04*

   Gold-plated moments of nucleon structure functions in baryon chiral perturbation theory

   Vadim Lensky (ITEP, Moscow)🇷🇺 · Jose Manuel Alarcón🇩🇪 · Vladimir Pascalutsa (KPH, U. Mainz)🇩🇪

   We obtain leading- and next-to-leading order predictions of chiral perturbation theory for several prominent moments of nucleon structure functions. These free-parameter free results turn out to be in overall agreement with the available empirical information on nearly all of the considered moments, in the region of low-momentum transfer ($Q^2<0.3$ GeV${}^2$). Especially surprising is the situation for the spin polarizability ${\delta }_{LT}$, which thus far was not reproducible in chiral perturbation theory for proton and neutron simultaneously. This problem, known as the "${\delta }_{LT}$ puzzle," is not seen in the present calculation.

   ↳ hep-phhep-latnucl-exnucl-thPRC(2014)·65 citations
5. 05*

   Comments on "A Dark Matter Search with MALBEK"

   J.I. Collar🇺🇸

   CoGeNT and MALBEK use p-type point contact germanium detectors to search for low-mass dark matter particles. Both detectors enjoy identical intrinsic noise characteristics. However, MALBEK's data acquisition electronics severely degrade the ability to separate signals originating in the bulk of the germanium crystal from surface backgrounds, through a measurement of the preamplifier pulse rise-time in the sub-keVee energy range of interest. The physical meaning of the parameter W${}_{par}$ developed by the MAJORANA collaboration to compensate for this limitation is clarified here. It is shown that this parameter does not correlate to rise-time at low energy, and is presently unable to distinguish between surface and bulk events below $\sim$1 keVee. This leads to a sizable overstatement of MALBEK's sensitivity to low-mass dark matter particles, when employing aggressive W${}_{par}$ cuts.

   ↳ physics.ins-detastro-ph.COastro-ph.IMhep-ex+12 citations
6. 06*

   $\Delta (1232)$ Resonance Contribution to Two-Photon Exchange in Electron-Proton Scattering Revisited

   Hai-Qing Zhou🇨🇳 · Shin Nan Yang🇹🇼

   We revisit the question of the contributions of two-photon exchange with $\Delta (1232)$ excitation to the electron-proton scattering in a hadronic model. Three improvements over the previous calculations are made, namely, correct vertex function for $\gamma N\to \Delta$, realistic $\gamma N\Delta$ form factors, and coupling constants. The discrepancy between the values of $R\equiv {\mu }_p{G}_E/G_M$ extracted from Rosenbluth technique and polarization transfer method can be reasonably accounted for if the data of Andivahis {\it et al.} \cite{Andivahis94} are analyzed. However, substantial discrepancy remains if the data of Qattan {\it et al.} \cite{Qattan05} are used. For the ratio $R^{\pm }$ between $e^{\pm }p$ scatterings, our predictions appear to be in satisfactory agreement with the preliminary data from VEPP-3. The agreement between our model predictions and the recent measurements on single spin asymmetry, transverse and longitudinal recoil proton polarizations ranges from good to poor.

   ↳ nucl-thhep-phnucl-exEPJA(2015)·40 citations
7. 07*

   MCNP6 Simulation of Reactions of Interest to FRIB, Medical, and Space Applications

   Stepan G. Mashnik🇺🇸

   The latest, production, version of the Los Alamos Monte Carlo N-Particle transport code MCNP6 has been used to simulate a variety of particle-nucleus and nucleus-nucleus reactions of academic and applied interest to the Facility for Rare Isotope Beams (FRIB), medical isotope production, space-radiation shielding, cosmic-ray propagation, and accelerator applications, including several reactions induced by radioactive isotopes, analyzing production of both stable and radioactive residual nuclei. Here, we discuss examples of validation and verification of MCNP6 compared to recent neutron spectra measured at the Heavy Ion Medical Accelerator in Chiba, Japan; to spectra of light fragments from several reactions measured recently at GANIL, France; INFN Laboratori Nazionali del Sud, Catania, Italy; COSY of the Julich Research Center, Germany; and to cross sections of products from several reactions measured lately at GSI, Darmstadt, Germany; ITEP, Moscow, Russia; LANSCE, LANL, Los Alamos, USA. As a rule, MCNP6 provides quite good predictions for most of the reactions we analyzed so far, allowing us to conclude that it can be used as a reliable and useful simulation tool for FRIB, medical, and space applications involving stable and radioactive isotopes.

   ↳ nucl-thnucl-exJPS Conf.Proc.(2015)·1 citation
8. 08*

   Experimental study of rare charged pion decays

   Dinko Pocanic🇺🇸 · Emil Frlez🇺🇸 · Andries van der Schaaf🇨🇭

   The combination of simple dynamics, small number of available decay channels, and extremely well controlled radiative and loop corrections, make charged pion decays a sensitive means for testing the underlying symmetries and the universality of weak fermion couplings, as well as for improving our understanding of pion structure and chiral dynamics. This paper reviews the current state of experimental study of the allowed rare decays of charged pions: (a) leptonic, ${\pi }^{+}\to e^{+}{\nu }_e$, or ${\pi }_{e2}$, (b) radiative, ${\pi }^{+}\to e^{+}{\nu }_e\gamma$, or ${\pi }_{e2\gamma }$, and ${\pi }^{+}\to e^{+}{\nu }_e{e}^{+}{e}^{-}$, or ${\pi }_{e2ee}$, and (c) semileptonic, ${\pi }^{+}\to {\pi }^0{e}^{+}\nu$, or ${\pi }_{e3}$. Taken together, the combined data set presents an internally consistent picture that also agrees well with standard model predictions. The internal consistency is illustrated well by the ${\pi }_{e2}$ branching ratio of $(R_{e/\mu }^{\pi }{)}^{\mathrm{PIBETA}}=(1.2366\pm 0.0064)\times 10^{-4}$ extracted in this work from the PIBETA measurement of the ${\pi }_{e3}$ decay and the current best value for the CKM matrix element $V_{ud}$. However, even after the great progress of the recent decades, experimental precision is lagging far behind that of the theoretical description for all above processes. We review the implications of the present state of knowledge and prospects for further improvement in the near term.

   ↳ hep-exhep-phnucl-exJ.Phys.G(2014)·24 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.