2,856 research outputs found
Majorana neutrino signals at Belle-II and ILC
For some theoretical and experimental considerations, the relatively light
Majorana neutrinos at the GeV scale have been attracting some interest. In this
article we consider a scenario with only one Majorana neutrino , negligible
mixing with the active neutrinos , where the Majorana neutrino
interactions could be described in a model independent approach based on an
effective theory. Under such a framework, we particularly study the feasibility
of observing the with mass in the range 030 GeV via the process e^+ e^-
\to \nu N \to\gamma + \slashed E in the future Belle-II and ILC experiments.
The results show that it is unpromising for Belle-II to observe the signal,
while ILC may easily make a discovery for the Majorana neutrino.Comment: 14 pages, 7 figures, 2 table
Cell aggregation induces phosphorylation of PECAM-1 and Pyk2 and promotes tumor cell anchorage-independent growth
<p>Abstract</p> <p>Background</p> <p>Apoptosis caused by inadequate or inappropriate cell-matrix interactions is defined as anoikis. Although transformed cells are known to be anoikis-resistant, the underlying mechanisms have not been well understood. We investigated the mechanisms of anoikis resistance of tumor cells.</p> <p>Results</p> <p>We observed that cell aggregation in suspension promoted cell survival and proliferation. We demonstrated a correlation between tumor cell aggregation in suspension and cell growth in soft agar. Analysis of tyrosine kinase-mediated cell survival and growth signaling pathways revealed increased levels of tyrosine-phosphorylation of PECAM-1 and Pyk2 in cell aggregates. We also showed that PECAM-1 and Pyk2 physically interact with each other, and that PECAM-1 carrying a deletion of exons 11-16 could no longer bind to Pyk2. Furthermore, RNA interference-mediated reduction of Pyk2 and PECAM-1 protein levels reduced cell aggregation and inhibited the growth of tumor cells in soft agar.</p> <p>Conclusions</p> <p>The data demonstrated that Pyk2 and PECAM-1 were critical mediators of both anchorage-independent growth and anoikis resistance in tumor cells.</p
Precise QCD predictions on top quark pair production mediated by massive color octet vector boson at hadron colliders
We present a theoretical framework for systematically calculating
next-to-leading order (NLO) QCD effects to various experimental observables in
models with massive COVB in a model independent way at hadron colliders.
Specifically, we show the numerical results for the NLO QCD corrections to
total cross sections, invariant mass distribution and AFB of top quark pairs
production mediated by a massive COVB in both the fixed scale (top quark mass)
scheme and the dynamical scale (top pair invariant mass) scheme. Our results
show that the NLO QCD calculations in the dynamical scale scheme is more
reasonable than the fixed scheme and the naive estimate of the NLO effects by
simple rescaling of the LO results with the SM NLO K-factor is not appropriate.Comment: 6 pages, 5 figures, 2 tables; version published in EPJ
The -meson longitudinal leading-twist distribution amplitude
In the present paper, we suggest a convenient model for the vector
-meson longitudinal leading-twist distribution amplitude
, whose distribution is controlled by a single parameter
. By choosing proper chiral current in the correlator, we obtain
new light-cone sum rules (LCSR) for the TFFs , and ,
in which the -order provides dominant
contributions. Then we make a detailed discussion on the
properties via those TFFs. A proper choice of can
make all the TFFs agree with the lattice QCD predictions. A prediction of
has also been presented by using the extrapolated TFFs, which
indicates that a larger leads to a larger . To
compare with the BABAR data on , the longitudinal leading-twist
DA prefers a doubly-humped behavior.Comment: 7 pages, 3 figures. Discussions improved and references updated. To
be published in Phys.Lett.
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