76 research outputs found
Polarized lepton pair forward-backward asymmetries in (B -> K^* l^+ l^-) decay beyond the standard model
We study the polarized lepton pair forward-backward asymmetries in (B -> K^*
l^+ l^-) decay using a general, model independent form of the effective
Hamiltonian. We present the general expression for nine double-polarization
forward-backward asymmetries. It is shown that, the study of the
forward-backward asymmetries of the doubly-polarized lepton pair is a very
useful tool for establishing new physics beyond the standard model.Comment: 29 pages, 18 figures, LaTeX formatte
General analysis of CP violation in polarized (b -> d l^+ l^-) decay
The CP violating asymmetries in the (b -> d l^+ l^-) decay, when one of the
leptons is polarized, is investigated using the most general form of the
effective Hamiltonian. The sensitivity of the CP violating asymmetries on the
new Wilson coefficients is studied.Comment: 25 pages, 20 figures, LaTeX formatte
Light vector meson octet-decuplet baryon vertices in QCD
The strong coupling constants between light vector mesons and octet-decuplet
baryons are calculated in framework of the light cone QCD sum rules, taking
into account SU(3) flavor symmetry breaking effects. It is shown that all
strong coupling constants can be represented in terms of a single universal
function. Size of the SU(3) symmetry breaking effects are estimated.Comment: 27 pages, 6 figures, LaTeX formatte
Vector meson dominance and radiative decays of heavy spin-3/2 baryons to heavy spin--1/2 baryons
Using the calculated values of the strong coupling constants of the heavy
sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with
light mesons within the light cone QCD sum rules method, and vector meson
dominance assumption, the radiative decay widths are calculated. These widths
are compared with the "direct" radiative decay widths predicted in the
framework of the light cone QCD sum rules.Comment: 8 pages, no figures, LaTeX formatte
Double-lepton polarization asymmetries in the Exclusive (B -> rho l^+ l^-) decay beyond the Standard Model
The double-lepton polarization asymmetries in (B -> rho l^+ l^-) decay is
analyzed in a model independent framework. The general expressions for nine
double-polarization asymmetries are calculated. It is shown that the study of
the double-lepton polarization asymmetries proves to be very useful tool in
looking for new physics beyond the standard model.Comment: 28 pages, 16 figures, LaTeX formatte
Pseudoscalar--meson decuplet--baryon coupling constants in light cone QCD
Taking into account the breaking effects, the strong coupling
constants of the , and mesons with decuplet baryons are
calculated within light cone QCD sum rules method. It is shown that all
coupling constants, even in the case of breaking, are described in
terms of only one universal function. It is shown that for transition violation of symmetry is very large
and for other channels when symmetry is violated, its maximum value
constitutes .Comment: 17 Pages, one Figure and 3 Table
Vector meson-baryon strong coupling contants in light cone QCD sum rules
Using the most general form of the interpolating current of the baryons, the
strong coupling constants of the light vector mesons with the octet baryons are
calculated within the light cone QCD sum rules. The SU(3)_f symmetry breaking
effects are taken into account in the calculations. It is shown that each of
the electric and magnetic coupling constants can be described in terms of three
universal functions. A detailed comparison of the results of this work on
aforementioned couplings with the existing theoretical results is presented.Comment: 25 pages, 4 figures, LaTeX formatte
Involvement of the histaminergic system in the resuscitating effect of centrally acting leptin in haemorrhagic shock in rats
Leptin, acting centrally as a neuromodulator, induces the activation of the sympathetic nervous system, which may lead to a pressor action in normotensive animals. In haemorrhagic shock, leptin administered intracerebroventricularly (icv.) evokes the resuscitating effect, with long-lasting rises in mean arterial pressure (MAP) and heart rate (HR), subsequent increase in peripheral blood flows, and a 100% survival at 2 h. Since leptin is able to activate histaminergic neurons, and centrally acting histamine also induces the resuscitating effect with the activation of the sympathetic nervous system, in the present study, we investigated an involvement of the histaminergic system in leptin-evoked cardiovascular effects in haemorrhagic shock. The model of irreversible haemorrhagic shock, with MAP decreased to and stabilised at 20 - 25 mmHg, has been used. Leptin (20 μg) given icv. at 5 min of critical hypotension evoked 181.5% increase in extracellular hypothalamic histamine concentration during the first 10 min after injection. Rises in MAP, HR and renal, mesenteric and hindquarters blood flows induced by leptin were inhibited by icv. pre-treatment with histamine H1 receptor antagonist chlorpheniramine (50 nmol). In contrast, there was no effect of H2, H3 and H4 receptor antagonists ranitidine (25 nmol), VUF 5681 (25 nmol) and JNJ 10191584 (25 nmol), respectively. In conclusion, the histaminergic system is involved in centrally-acting leptin-induced resuscitating effect in haemorrhagic shock in rats
The "radiative Delta -> N gamma" decay in light cone QCD
The "g_{Delta N gamma}" coupling for the "Delta -> N gamma" decay is
calculated in framework of the light cone QCD sum rules and is found to be
g_{Delta N gamma} = (1.6 pm 0.2) GeV^(-1). Using this value of g_{Delta N
gamma} we estimate the branching ratio of the Delta^+ -> N gamma decay, which
is in a very good agreement with the experimental result.Comment: 9 pages, 1figures, LaTeX formatte
Exclusive Lambda_b -> Lambda l^+ l^- decay in two Higgs doublet model
Rare Lambda_b -> Lambda l^+ l^- decay is investigated in framework of general
two Higgs doublet model, in which a new source of CP violation exists (model
III). The polarization parameter, CP asymmetry and decay width are calculated.
It is shown that CP asymmetry is a very sensitive tool for establishing model
III.Comment: 16 pages, 3 figures, LaTeX formatte
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