相关论文: Unparticle effects in rare (t -> c g g) decay
The radiative and leptonic decays of $\eta_c\to \gamma\gamma$ and $\eta_c\to l^+l^-$ are studied. For $\eta_c\to \gamma\gamma$ decay, the second-order electromagnetic tree-level diagram gives the leading contribution. The decay rate of…
Gravitational decays in particle physics are expected to violate the B and L quantum numbers. In the standard theory, where gravity is weak because of the huge value of Planck mass, the observation of the phenomenon is far from present and…
We predict the branching ratios of the lepton flavor violating Z boson decays Z\to e^{\pm} \mu^{\pm}, Z\to e^{\pm} \tau^{\pm} and Z\to \mu^{\pm} \tau^{\pm} in the case that the lepton flavor violation is carried by the scalar unparticle…
I present the Standard Model calculation of the decay rate for b -> s g (g denotes a gluon) at next-to-leading logarithms (NLL). In order to get a meaningful physical result, the decay b -> s g g and certain contributions of b -> s \bar{f}…
Flavour physics represents a unique test bench for the Standard Model (SM). New analyses performed at the LHC experiments are now providing unprecedented insights into CKM metrology and new evidences for rare decays. The CKM picture can…
The transitions $B_{s,d}\rightarrow \ell^+\ell^-$ (for $\ell=e, \mu, \tau$), although extremely suppressed within the SM, are exceptionally clean channels particularly sensitive to New Physics contributions. So far only the branching ratio…
We investigate to what extent the recently measured value for a non-vanishing direct CP asymmetry in D0 -> K+ K- and D0 -> pi+ pi- decays can be accommodated in the Standard Model (SM) or extensions with a constrained flavour sector, for…
Rare decays of the Z boson provide a sensitive probe for physics beyond the Standard Model (SM). This study investigates the $e^{+}e^{-} \to Z \to \nu\bar{\nu}\gamma$ process within the context of the Tera-Z programmes at future colliders…
Effects of supersymmetric particles on flavor changing neutral current and lepton flavor violating processes are studied in the supersymmetric SU(5) grand unified theory with right-handed neutrino supermultiplets. Using input parameters…
We show that it is essential to include renormalisation group (RG) effects for determining the SMEFT parameter space consistent with the CDF W-mass anomaly at the matching scale. This is because operators that are only weakly…
We calculate the electroweak-like one-loop supersymmetric contributions to the rare and flavor-violating decay of the top quark into a charm quark and a gauge boson: $t->c V$, with $V=\gamma,Z,g$. We consider loops of both charginos and…
In this paper, we analyze different decay observables of semileptonic $ B_c$ decays into $(D_(s,d)^((*))){\mu}^+ {\mu}^-$ such as branching ratio, forward-backward asymmetry, polarization fraction and lepton polarization asymmetry in the…
We perform a comprehensive study of a number of rare charm decays, incorporating the first evaluation of the QCD corrections to the short distance contributions, as well as examining the long range effects. For processes mediated by the…
New physics in the rare top decays $t \to q \ell^+\ell^-$ is currently very weakly constrained. We show that in a large class of Standard Model extensions, existing experimental constraints on new physics in flavor-conserving processes…
Recently we have presented an analysis of flavor changing neutral coupling mediated radiative top quark decays at next-to-leading order in QCD. In the present paper we provide the details of the calculation of QCD corrections to t-> q gamma…
The ``anarchic'' Randall-Sundrum model of flavor is a low energy solution to both the electroweak hierarchy and flavor problems. Such models have a warped, compact extra dimension with the standard model fermions and gauge bosons living in…
In this paper, we study the effects of the unparticles on the parity-violating asymmetry for the low energy electron-electron scattering, $e^-e^-\to e^-e^-$. Using the data from the E158 experiment at SLAC we extract the limits on the…
Kaluza-Klein fields characterizing, from a four-dimensional viewpoint, the presence of compact universal extra dimensions would alter low-energy observables through effects determined by some compactification scale, $R^{-1}$, since the…
The rare decay $b \to s \gamma$ is studied in the left-right supersymmetric model. We give explicit expressions for all the amplitudes associated with the supersymmetric contributions coming from gluinos, charginos and neutralinos in the…
The flavor-changing neutral current decay processes of the $B$ and $B_c$ mesons with the final states involving spin-$1/2$ particles are investigated. By considering the background of the Standard Model where $\nu\bar\nu$ contributes the…