0000000000069752
AUTHOR
Sascha Turczyk
Non-cancellation of electroweak logarithms in high-energy scattering
We study electroweak Sudakov corrections in high energy scattering, and the cancellation between real and virtual Sudakov corrections. Numerical results are given for the case of heavy quark production by gluon collisions involving the rates $gg \to t \bar t, b \bar b, t \bar b W, t \bar t Z, b \bar b Z, t \bar t H, b \bar b H$. Gauge boson virtual corrections are related to real transverse gauge boson emission, and Higgs virtual corrections to Higgs and longitudinal gauge boson emission. At the LHC, electroweak corrections become important in the TeV regime. At the proposed 100 TeV collider, electroweak interactions enter a new regime, where the corrections are very large and need to be re…
Taming the higher power corrections in semileptonic B decays
We study the effect of dimension 7 and 8 operators on inclusive semileptonic B decays and the extraction of |Vcb|. Using moments of semileptonic B decay spectra and information based on the Lowest-Lying State saturation Approximation (LLSA) we perform a global fit of the nonperturbative parameters of the heavy quark expansion including for the first time the O(1/mb^{4,5}) contributions. Higher power corrections appear to have a very small effect on the extraction of |Vcb|, independently of the weight we attribute to the LLSA.
New ways to search for right-handed current inB→ρℓν¯decay
An interesting possibility to ease the tension between various determinations of $|{V}_{ub}|$ is to allow a small right-handed contribution to the standard model weak current. The present bounds on such a contribution are fairly weak. We propose new ways to search for such a beyond standard model contribution in semileptonic $B\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\ell}\overline{\ensuremath{\nu}}$ decay. Generalized asymmetries in one, two, or three angular variables are introduced as discriminators, which do not require an unbinned analysis of the fully differential distribution, and a detailed study of the corresponding theoretical uncertainties is performed. A discussion o…
Resolved Power Corrections to the Inclusive DecayB‾→Xsℓ+ℓ−
We identify the correct power counting of all the variables in the low-q2 window of the inclusive decay B‾→Xs within the effective theory SCET if a hadronic mass cut is imposed. Furthermore we analyse the resolved power corrections at the order 1/mb in a systematic way. The resolved contributions – as a special feature – stay nonlocal when the hadronic mass cut is released. Thus, they represent an irreducible uncertainty independent of the hadronic mass cut.
A new way to search for right-handed currents in semileptonic B→ρℓν‾ decay
AbstractThere exist a long standing tension among determinations of the CKM matrix element |Vub| from various (semi)leptonic B decay channels with varying significance of up to ∼3σ. An interesting possibility to ease this tension is to allow for a right-handed contribution to the standard model left-handed weak current mediating the b→u quark decay. Current bounds on such a contribution are fairly weak. We propose a new way to search for such a right-handed current in semileptonic B→ρ meson decays. We describe a new variable that we propose, and discuss the theoretical uncertainties. Especially we investigate the uncertainties and their correlations among all contributing form factors with …
New ways to search for right-handed current in B -> rho ell nu decay
An interesting possibility to ease the tension between various determinations of |V_{ub}| is to allow a small right-handed contribution to the standard model weak current. The present bounds on such a contribution are fairly weak. We propose new ways to search for such a beyond standard model contribution in semileptonic B -> rho ell nu decay. Generalized asymmetries in one, two, or three angular variables are introduced as discriminators, which do not require an unbinned analysis of the fully differential distribution, and a detailed study of the corresponding theoretical uncertainties is performed. A discussion on how binned measurements can access all the angular information follows, whi…