Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userQCD Corrections to Scalar Quark Decays
67
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In supersymmetric theories, the main decay modes of scalar quarks are decays into quarks plus charginos or neutralinos, if the gluinos are heavy enough. We calculate the O($alpha_s$) QCD corrections to these decay modes in the minimal supersymmetric extension of the Standard Model. In the case of scalar top and bottom quarks, where mixing effects can be important, these corrections can reach values of the order of a few ten percent. They can be either positive or negative and increase logarithmically with the gluino mass. For the scalar partners of light quarks, the corrections do not exceed in general the level of ten percent for gluino masses less than 1 TeV.
rate research
Read More
In supersymmetric theories, the decays of the neutral CP-even and CP-odd as well as the charged Higgs bosons into scalar quarks, in particular into top and bottom squarks, can be dominant if they are kinematically allowed. We calculate the QCD corrections to these decay modes in the minimal supersymmetric extension of the Standard Model, including all quark mass terms and squark mixing. These corrections turn out to be rather large, altering the decay widths by an amount which can be larger than 50%. The corrections can be either positive or negative, and depend strongly on the mass of the gluino. We also discuss the QCD corrections to the decays of heavy scalar quarks into light scalar quarks and Higgs bosons.
We calculate the radiative corrections to the nonleptonic inclusive B decay mode $brightarrow cbar u d$ taking into account the charm quark mass. Compared to the massless case, corrections resulting from a nonvanishing c quark mass increase the nonleptonic rate by (4--8)%, depending on the renormalization point. As a by--product of our calculation, we obtain an analytic expression for the radiative correction to the semileptonic decay $brightarrow utaubar u$ taking into account the $tau$ lepton mass, and estimate the c quark mass effects on the nonleptonic decay mode $brightarrow cbar c s$.
We present partial results on NLO and NNLO QCD, and NLO electroweak corrections to polarized top quark decays. In parallel we derive positivity bounds for the polarized structure functions in polarized top quark decays and check them against the perturbative corrections to the structure functions.
We present a complete next-to-leading order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion ($bbar{b} to hh$) at the CERN Large Hadron Collider (LHC) in the Standard Model. The NLO QCD corrections lead to less dependence on the renormalization scale ($mu_R$) and the factorization scale ($mu_F$) than the leading-order (LO) cross section, and they significantly increase the LO cross section. The rate for inclusive Higgs pair production is small in the Standard Model, but can be large in models with enhanced couplings of the $b$ quark to the Higgs bosons.
We consider top quark pair production in association with a hard jet through next-to-leading order in perturbative QCD. Top quark decays are treated in the narrow width approximation and spin correlations are retained throughout the computation. We include hard jet radiation by top quark decay products and explore their importance for basic kinematic distributions at the Tevatron and the LHC. Our results suggest that QCD corrections and jet radiation in decays can lead to significant changes in shapes of basic distributions and, therefore, need to be included for the description of ttbar+jet production. We compare the shape of the transverse momentum distribution of a top quark pair recently measured by the D0 collaboration with the result of our computation and find reasonable agreement.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
