Thu·Aug 25, 2011Thursday·August 25, 2011

1. 01*

   Experimental Challenges of the N* Program

   Ralf W. Gothe🇺🇸

   The first challenge faced in investigating the strong interaction from partially explored, where meson-cloud degrees of freedom dominate, to still unexplored distance scales, where the dressed-quark contributions are the dominating degrees of freedom, is to find an experiment that allows to measure observables that are probing this evolving nonperturbative QCD regime over the full range. Baryon spectroscopy can establish more sensitively, and in an almost model-independent way, nucleon excitation and non-resonant reaction amplitudes by complete measurements of pseudo-scalar meson photoproduction off nucleons. Elastic and transition form factors can then trace this evolution by measurements of elastic electron scattering and exclusive single-meson and double-pion electroproduction cross sections off the nucleon that will be extended to higher momentum transfers with the energy-upgraded CEBAF beam at JLab to study the dressed quark degrees of freedom, where their strong interaction is responsible for the ground and excited nucleon state formations. After establishing unprecedented high-precision data, the immanent next challenge is a high-quality analysis to extract these relevant electrocoupling parameters for various resonances that then can be compared to state of the art models and QCD-based calculations. Recent results demonstrate the status of the analysis and pinpoint further challenges, including those to establish QCD-based results directly from the experimental data.

   nucl-exhep-exAIP Conf.Proc.(2012)·12 citations
2. 02*

   CUORE crystal validation runs: results on radioactive contamination and extrapolation to CUORE background

   F. Alessandria🇮🇹 · E. Andreotti🇮🇹 · R. Ardito🇮🇹 · C. Arnaboldi🇮🇹 · F. T. Avignone III🇺🇸 · M. Balata🇮🇹 · I. Bandac🇺🇸 · T. I. Banks🇺🇸 · G. Bari🇮🇹 · J. W. Beeman🇺🇸 · F. Bellini🇮🇹 · A. Bersani🇮🇹 and 107 other authors

   The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performances and the radiopurity of the TeO${}_2$ crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.

   nucl-exAstropart.Phys.(2012)·100 citations
3. 03*

   Nuclear Data Resources for Capture gamma-Ray Spectroscopy and Related Topics

   B. Pritychenko

   Nuclear reaction data play an important role in nuclear reactor, medical, and fundamental science and national security applications. The wealth of information is stored in internally adopted ENDF-6 and EXFOR formats. We present a complete calculation of resonance integrals, Westcott factors, thermal and Maxwellian-averaged cross sections for Z=1-100 using evaluated nuclear reaction data. The addition of newly-evaluated neutron reaction libraries, and improvements in data processing techniques allows us to calculate nuclear industry and astrophysics parameters, and provide additional insights on all currently available neutron-induced reaction data. Nuclear reaction calculations will be discussed and an overview of the latest reaction data developments will be given.

   ↳ astro-ph.SRnucl-ex0 citations
4. 04*

   Next-to leading order analysis of target mass corrections to structure functions and asymmetries

   L. T. Brady🇺🇸 · A. Accardi🇺🇸 · T. J. Hobbs🇺🇸 · W. Melnitchouk🇺🇸

   We perform a comprehensive analysis of target mass corrections (TMCs) to spin-averaged structure functions and asymmetries at next-to-leading order. Several different prescriptions for TMCs are considered, including the operator product expansion, and various approximations to it, collinear factorization, and xi-scaling. We assess the impact of each of these on a number of observables, such as the neutron to proton F_2 structure function ratio, and parity-violating electron scattering asymmetries for protons and deuterons which are sensitive to gamma-Z interference effects. The corrections from higher order radiative and nuclear effects on the parity-violating deuteron asymmetry are also quantified.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2011)·49 citations
5. 05*

   Roy-Steiner equations for $\gamma \gamma \to \pi \pi$

   Martin Hoferichter🇩🇪 · Daniel R. Phillips🇺🇸 · Carlos Schat🇺🇸

   Starting from hyperbolic dispersion relations, we present a system of Roy--Steiner equations for pion Compton scattering that respects analyticity and unitarity requirements, gauge invariance, as well as crossing symmetry, and thus all symmetries of the underlying quantum field theory. To suppress the dependence on the high-energy region, we also consider once- and twice-subtracted versions of the equations, where the subtraction constants are identified with dipole and quadrupole pion polarizabilities. We consider the resolution of the $\gamma \gamma \to \pi \pi$ partial waves by a Muskhelishvili-Omnès representation with finite matching point, and discuss the consequences for the two-photon coupling of the $\sigma$ resonance as well as its relation to pion polarizabilities.

   ↳ hep-phhep-exnucl-exnucl-th3 citations
6. 06*

   Eta-photoproduction in a gauge-invariant chiral unitary framework

   Dino Ruic🇩🇪 · Maxim Mai🇩🇪 · Ulf-G. Meissner🇩🇪

   We analyse photoproduction of eta mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S11(1535) is extracted. An extension of the kernel is also discussed.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2011)·34 citations
7. 07*

   A Prototype Detector for Directional Measurement of the Cosmogenic Neutron Flux

   J. Lopez🇺🇸 · K. Terao🇺🇸 · J.M. Conrad🇺🇸 · D. Dujmic🇺🇸 · L. Winslow🇺🇸

   This paper describes a novel directional neutron detector prototype. The low pressure time projection chamber uses a mix of helium and CF4 gases. The detector reconstructs the energy and angular distribution of fast neutron recoils. This paper reports results of energy calibration using an alpha source and angular reconstruction studies using a collimated neutron source. The best performance is obtained with a 12.5% CF4 gas mixture. At low energies the target for fast neutrons transitions is primarily helium, while at higher energies, the fluorine contributes as a target. The reconstruction efficiency is both energy and target dependent. For neutrons with energies less than 20 MeV, the reconstruction efficiency is ~40% for fluorine recoils and ~60% for helium recoils.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2012)·10 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.