Nuclear Theory·nucl-th

Wednesday·October 21, 2015

10 papers—6 primary·4 cross-listed

07
[Submitted on 19 Oct 2015] (cross-list from hep-ph)
Model-independent determination of the axial mass parameter in quasielastic antineutrino-nucleon scattering
Bhubanjyoti Bhattacharya🇨🇦 · Gil Paz🇺🇸 · Anthony J. Tropiano🇺🇸
Understanding the charged current quasielestic (CCQE) neutrino-nucleus interaction is important for precision studies of neutrino oscillations. The theoretical description of the interaction depends on the combination of a nuclear model with the knowledge of form factors. While the former has received considerable attention, the latter, in particular the axial form factor, is implemented using the historical dipole model. Instead, we use a model-independent approach, presented in a previous study, to analyze the muon antineutrino CCQE mineral oil data published by the MiniBooNE collaboration. We combine the cross section for scattering of antineutrinos off protons in carbon and hydrogen, using the same axial form factor for both. The extracted value of the axial mass parameter $m_{A} = 0.8 4_{- 0.04}^{+ 0.12} \pm 0.11 GeV$ is in very good agreement with the model-independent value extracted from MiniBooNE's neutrino data. Going beyond a one-parameter description of the axial form factor, we extract values of the axial form factor in the range of $Q^{2} = 0.1...1.0$ GeV $^{2}$ , finding a very good agreement with the analogous extraction from the neutrino data. We discuss the implications of these results.
Comments:
13 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1510.05652 [pdf]
PRD(2015)·39 citations
08
[Submitted on 20 Oct 2015] (cross-list from hep-ph)
Three-gluon correlator contribution to Sivers asymmetry in SIDIS
Ling-Yun Dai🇺🇸
We study the Sivers asymmetry in semi-inclusive deep inelastic scattering: the three-gluon correlation function contribution. At the cross section level, we establish the matching between the twist-3 collinear factorization approach and the transverse momentum dependent factorization formalism at the moderate transverse momentum region. The so-called coefficient functions when one expands the quark Sivers function in terms of three-gluon correlation functions are derived, which are essential components in the usual transverse momentum dependent evolution formalism. Finally we calculate the transverse-momentum-weighted spin-dependent differential cross section at the next-to-leading order, from which we identify the off-diagonal/three-gluon correlation contribution to the QCD collinear evolution of the twist-3 Qiu-Sterman function.
Comments:
7 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1510.05748 [pdf]
PoS(2015)·0 citations
09
[Submitted on 20 Oct 2015] (cross-list from hep-lat)
Neutron electric dipole moment using $N_{f} = 2 + 1 + 1$ twisted mass fermions
C. Alexandrou (Univ. of Cyprus and Cyprus Inst.)🇨🇾 · A. Athenodorou (Univ. of Cyprus and Cyprus Inst.)🇨🇾 · M. Constantinou (Univ. of Cyprus and Cyprus Inst.)🇨🇾 · K. Hadjiyiannakou (Univ. of Cyprus and Cyprus Inst.)🇨🇾 · K. Jansen (NIC, DESY-Zeuthen)🇩🇪 · G. Koutsou (Cyprus Inst.)🇨🇾 · K. Ottnad (Univ. of Cyprus and Bonn Univ.)🇨🇾 · M. Petschlies (Cyprus Inst. and Bonn Univ.)🇨🇾
We evaluate the neutron electric dipole moment $∣ d_{N} ∣$ using lattice QCD techniques. The gauge configurations analyzed are produced by the European Twisted Mass Collaboration using $N_{f} = 2 + 1 + 1$ twisted mass fermions at one value of the lattice spacing of $a ≃ 0.082 fm$ and a light quark mass corresponding to $m_{π} ≃ 373 MeV$ . Our approach to extract the neutron electric dipole moment is based on the calculation of the $C P$ -odd electromagnetic form factor $F_{3} (Q^{2})$ for small values of the vacuum angle $θ$ in the limit of zero Euclidean momentum transfer $Q^{2}$ . The limit $Q^{2} \to 0$ is realized either by adopting a parameterization of the momentum dependence of $F_{3} (Q^{2})$ and performing a fit, or by employing new position space methods, which involve the elimination of the kinematical momentum factor in front of $F_{3} (Q^{2})$ . The computation in the presence of a $C P$ -violating term requires the evaluation of the topological charge $Q$ . This is computed by applying the cooling technique and the gradient flow with three different actions, namely the Wilson, the Symanzik tree-level improved and the Iwasaki action. We demonstrate that cooling and gradient flow give equivalent results for the neutron electric dipole moment. Our analysis yields a value of $∣ d_{N} ∣ = 0.045 (6) (1) θ ˉ e \cdot fm$ for the ensemble with $m_{π} = 373$ MeV considered.
Comments:
Version accepted for publication in Phys. Rev. D.: 33 pages, 13 Figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1510.05823 [pdf]
PRD(2016)·52 citations
10
[Submitted on 20 Oct 2015] (cross-list from hep-ph)
Long-range properties of $1 S$ bottomonium states
Nora Brambilla🇩🇪 · Gastão Krein🇧🇷 · Jaume Tarrús Castellà🇩🇪 · Antonio Vairo🇩🇪
In the framework of weakly-coupled pNRQCD, we derive, first, an analytical expression for the chromo-polarizability of $1 S$ -bottomonium states in agreement with previous determinations. Then we use the QCD trace anomaly to obtain the two-pion production amplitude for the chromo-polarizability operator and match the result to a chiral effective field theory with $1 S$ -bottomonium states and pions as degrees-of-freedom. In this chiral effective field theory we compute some long-range properties of the $1 S$ bottomonium generated by the pion coupling such as the leading chiral logarithm to the $1 S$ -bottomonium mass and the van der Waals potential between two $1 S$ -bottomonium states. Both results improve on previously known expressions.
Comments:
24 pages, 10 figures. Journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1510.05895 [pdf]
PRD(2016)·77 citations

Affiliations

first authorsco-authorsvia INSPIRE

Model-independent determination of the axial mass parameter in quasielastic antineutrino-nucleon scattering

Three-gluon correlator contribution to Sivers asymmetry in SIDIS

Neutron electric dipole moment using Nf​=2+1+1 twisted mass fermions

Long-range properties of 1S bottomonium states

Affiliations

Neutron electric dipole moment using $N_{f} = 2 + 1 + 1$ twisted mass fermions

Long-range properties of $1 S$ bottomonium states