524 research outputs found
Effect of neutrino trapping on the three flavor FFLO phase of QCD
We compute the effect of a non-zero lepton chemical potential on the
structure of the three flavor Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase of
QCD at finite temperature. We show that, as in the BCS case, the lepton
chemical potential favors two-species color superconductivity and disfavors the
three species pairing. We stress that this study could be relevant for the
cooling of a proto-neutron star with a FFLO core, if the temperatures are
higher than the un-trapping temperature.Comment: 12 pages, 2 figures, RevTeX4 class. Changed Fig. 2 (see text) and
some reference adde
Semileptonic decays in the limit of a heavy daughter quark
The rate of the semileptonic decay b to c l v is calculated with order
alphas^2 accuracy, as an expansion around the limit of equal masses of the b
and c quarks. Recent results obtained around the limit of the c-quark much
lighter than b are confirmed. Details of the new expansion method are
described.Comment: 7 pages, 5 figure
Semi-Leptonic b-decay at Intermediate Recoil
We compute the O(\alpha_s^2) corrections to the differential rate of the
semileptonic decay b -> clv at the "intermediate recoil" point, where the
c-quark mass and the invariant mass of the leptons are equal. The calculation
is based on an expansion around two opposite limits of the quark masses
m_{b,c}: m_c ~ m_b and m_c << m_b. The former case was previously studied; we
correct and extend that result. The latter case is new. The smooth matching of
both expansions provides a check of both. We clarify the discrepancy between
the recent determinations of the full NNLO QCD correction to the semileptonic b
-> c rate, and its earlier estimate.Comment: 9 pages, 6 figures, Replaced figures, small format and typo
corrections, added appendix and reference
Vibrationally resolved NO dissociative excitation cross sections by electron impact
A theoretical investigation of the dissociative excitation by electron impact
on the NO molecule is presented, aiming to make up for the lack of data for
this process in the literature. A full set of vibrationally-resolved cross
sections and corresponding rate coefficients are calculated using the
Local-Complex-Potential approach and five resonant states of NO^-.Comment: 5 pages, 3 figure
Electroweak Fermion-loop Contributions to the Muon Anomalous Magnetic Moment
The two-loop electroweak corrections to the anomalous magnetic moment of the
muon, generated by fermionic loops, are calculated. An interesting role of the
top quark in the anomaly cancellation is observed. New corrections, including
terms of order , are computed and a class of diagrams
previously thought to vanish are found to be important. The total fermionic
correction is which decreases the electroweak
effects on , predicted from one-loop calculations, by 12\%. We give an
updated theoretical prediction for of the muon.Comment: Corrected versio
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