Constraints on a New Light Spin-One Particle from Rare b -> s Transitions

The anomalously large like-sign dimuon charge asymmetry in semileptonic b-hadron decays recently measured by the D0 Collaboration may be hinting at the presence of CP-violating new physics in the mixing of B_s mesons. It has been suggested that the effect of a nonstandard spin-1 particle lighter than the b quark with flavor-changing couplings to b and s quarks can reproduce the D0 result within its one-sigma range. Here we explore the possibility that the new particle also couples to charged leptons l=e,mu and thus contributes to rare b -> s processes involving the leptons. We consider in particular constraints on its couplings from existing experimental data on the inclusive B -> X_s l^+ l^- and exclusive B -> K^{(*)} l^+ l^- decays, as well as the anomalous magnetic moments of the leptons. We find that there is parameter space of the particle that is allowed by the current data. Future measurements of these B transitions and rare decays of the B_s meson, such as B_s -> (phi,eta,eta') l^+ l^- and B_s -> l^+ l^-, at LHCb and next-generation B factories can probe its presence or couplings more stringently.Comment: 19 pages, 5 figure

Splanchnic vein thrombosis in myeloproliferative neoplasms: Pathophysiology and molecular mechanisms of disease

Myeloproliferative neoplasms (MPNs) are the most common underlying prothrombotic disorder found in patients with splanchnic vein thrombosis (SVT). Clinical risk factors for MPN-associated SVTs include younger age, female sex, concomitant hypercoagulable disorders, and the JAK2 V617F mutation. These risk factors are distinct from those associated with arterial or deep venous thrombosis (DVT) in MPN patients, suggesting disparate disease mechanisms. The pathophysiology of SVT is thought to derive from local interactions between activated blood cells and the unique splanchnic endothelial environment. Other mutations commonly found in MPNs, including CALR and MPL, are rare in MPN-associated SVT. The purpose of this article is to review the clinical and molecular risk factors for MPN-associated SVT, with particular focus on the possible mechanisms of SVT formation in MPN patients

Pion structure in a nuclear medium

The structure and electroweak properties of the pion in symmetric nuclear matter are presented in the framework of the Nambu--Jona-Lasinio model. The pion is described as a bound state of a dressed quark-antiquark pair governed by the Bethe-Salpeter equation. For the in-medium current-light-quark properties we use the quark-meson coupling model, which describes successfully the properties of hadron in a nuclear medium. We found that the light-quark condensates, the pion decay constant and pion-quark coupling constant decrease with increasing nuclear matter density. We then predict the modifications of the charge radius of the charged pion in nuclear matter.Comment: 4 pages, 6 figures, accepted version for the QNP2018 proceedings, 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Ibaraki, Japa

Effects of medium modifications of nucleon form factors on neutrino scattering in dense matter

Effects of the in-medium modifications of nucleon form factors on neutrino interaction in dense matter are presented by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field and the quark-meson coupling models are respectively adopted for the effective nucleon mass and in-medium nucleon form factors. We calculate the cross-section of neutrino scattering as well as the neutrino mean free path. We found the cross sections of neutrino scattering in cold nuclear medium decreases when the in-medium modifications of the nucleon weak and electromagnetic form factors are taken into account.This reduction results in the enhancement of the neutrino mean free path, in particular at the baryon density of around a few times of the normal nuclear matter density.Comment: 4 pages, 2 figures, accepted for the QNP2018 proceedings, a talk given at QNP2018, 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Ibaraki, Japa

Stability and asymptotic behavior of periodic traveling wave solutions of viscous conservation laws in several dimensions

Under natural spectral stability assumptions motivated by previous investigations of the associated spectral stability problem, we determine sharp $L^p$ estimates on the linearized solution operator about a multidimensional planar periodic wave of a system of conservation laws with viscosity, yielding linearized $L^1\cap L^p\to L^p$ stability for all $p \ge 2$ and dimensions $d \ge 1$ and nonlinear $L^1\cap H^s\to L^p\cap H^s$ stability and $L^2$-asymptotic behavior for $p\ge 2$ and $d\ge 3$. The behavior can in general be rather complicated, involving both convective (i.e., wave-like) and diffusive effects