7,548 research outputs found
Discrimination of the light CP-odd scalars between in the NMSSM and in the SLHM
The presence of the light CP-odd scalar boson predicted in the
next-to-minimal supersymmetric model (NMSSM) and the simplest little Higgs
model (SLHM) dramatically changes the phenomenology of the Higgs sector. We
suggest a practical strategy to discriminate the underlying model of the CP-odd
scalar boson produced in the decay of the standard model-like Higgs boson. We
define the decay rate of "the non -tagged jet pair" with which we compute
the ratio of decay rates into lepton and jets. They show much different
behaviors between the NMSSM and the SLHM.Comment: 5 pages, 2 figures (5 figure files
Associated production of a single heavy T-quark in the littlest and simplest little Higgs models
The colored SU(2)-singlet heavy T-quark is one of the most crucial
ingredients in little Higgs models, which is introduced to cancel the largest
contribution of the SM top quark to the Higgs boson mass at one-loop level. In
two representative little Higgs models, the littlest Higgs model and the SU(3)
simplest Higgs model, we comprehensively study the single heavy T-quark
production at Large Hadron Collider (LHC). After presenting the possibility of
relatively light (~500 GeV) T-quark in the simplest little Higgs model, we
consider all the relevant processes, the 2->2 process of qb->q'T, the 2->3
process of qg->q'Tb, the s-channel process of q bar(q)'->T bar{b}, and the
gluon fusion process of gg->T bar{t}. We found that the 2->3 process can be
quite important, as its cross section is about 30% of the 2->2 one and it is
dominant in high p_T distributions. The s-channel and the gluon fusion
processes also show distinctive features in spite of their suppressed cross
sections. In the gluon fusion process of the simplest little Higgs model, for
example, the pseudo-scalar contribution is rather dominant over the Higgs
contribution for relatively light M_T.Comment: 27 pages, using RevTeX; references adde
Form Factors for Exclusive Semileptonic --Decays
We developed the new parton model approach for exclusive semileptonic decays
of -meson to by extending the inclusive parton model, and by
combining with the results of the HQET, motivated by Drell-Yan process. Without
the nearest pole dominance ans\"atze, we {\bf derived} the dependences of
hadronic form factors on . We also calculated numerically the slope of the
Isgur-Wise function, which is consistent with the experimental results.Comment: 20 pages, RevTex, 2 ps figure files(uuencoded in seperate file
The HCV Core Protein Acts as a Positive Regulator of Fas-Mediated Apoptosis in a Human Lymphoblastoid T Cell Line
AbstractHepatitis C virus (HCV) is a major human pathogen causing mild to severe liver disease worldwide and is remarkably efficient at establishing persistent infections. Previously, we have shown that the core protein has an immunomodulatory function including the suppression of T lymphocyte responses to viral infection. To investigate the underlying mechanism for the role of core protein in immune modulation, we examined the effect of core on the sensitivity of the human T cell line, Jurkat, to Fas-mediated apoptosis. The transient and stable expression of core protein in Jurkat cells increased the sensitivity of cells to Fas-mediated apoptosis when compared to control cells expressing vector DNA alone. In addition, we demonstrated that the core protein binds to the cytoplasmic domain of Fas which may enhance the downstream signaling event of Fas-mediated apoptosis. The expression of core protein did not alter the cell surface expression of Fas, indicating that the increased sensitivity of core-expressing cells to Fas ligand was not due to upregulation of Fas. Furthermore, we observed the augmentation of caspase-3 activity in core-expressing cells. These results suggest that the core protein may promote the apoptosis of immune cells during HCV infection via the Fas signaling pathway, thus facilitating HCV persistence
Time dependent CP asymmetry in decay to probe the origin of CP violation
Since the CP violation in the system has been investigated up to now only
through processes related to the -- mixing, urgently required is
new way of study for the CP violation and establishing its origin in the
system independent of the mixing process. In this work, we explore the
exclusive decay to obtain the time-dependent CP
asymmetry in decay process in the standard model and the
supersymmetric model. We find that the complex RL and RR mass insertion to the
squark sector in the MSSM can lead to a large CP asymmetry in
decay through the gluino-squark diagrams, which is not predicted in the
Standard Model induced by the -- mixing.Comment: 10 pages, 4 eps figure
Implication of the weak phase measured in decay
We explore the exclusive decay to obtain the
time-dependent CP asymmetry in decay process. We find that the
complex RL and RR mass insertion to the squark sector in the MSSM can lead to a
large deviation of CP asymmetry from that predicted in the Standard Model.Comment: 4 pages, talk given at the 32nd International Conference on High
Energy Physics (ICHEP'04), Beijing, China, 16-22 Aug. 200
- …