A5102734561- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atomic and Molecular Physics
- Muon and positron interactions and applications
- Neutrino Physics Research
- Computational Physics and Python Applications
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Advanced Chemical Physics Studies
- Quantum and Classical Electrodynamics
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Cosmology and Gravitation Theories
- Nuclear physics research studies
- Particle Detector Development and Performance
- Radioactive Decay and Measurement Techniques
- Quantum Mechanics and Applications
- Medical Imaging Techniques and Applications
- Experimental and Theoretical Physics Studies
- Scientific Measurement and Uncertainty Evaluation
University of Alberta
2015-2025
RWTH Aachen University
2021
Lodz University of Technology
2020
Quaid-i-Azam University
2019
European Organization for Nuclear Research
2010
Karlsruhe Institute of Technology
1994-2006
Brookhaven National Laboratory
1997-2006
University of Minnesota
2006
Institute of Nuclear Physics, Polish Academy of Sciences
1994-2006
TRIUMF
2006
Combining our results for various O(alpha[s]) corrections to the weak radiative B-meson decay, we are able present first estimate of branching ratio at next-to-next-to-leading order in QCD. We find B(B[over ]-->X[s]gamma)=(3.15+/-0.23) x 10(-4) Egamma>1.6 GeV B[over ]-meson rest frame. The four types uncertainties:nonperturbative (5%), parametric (3%), higher-order and m(c)-interpolation ambiguity (3%) have been added quadrature obtain total error.
The effects of strong interactions on the two-loop electroweak radiative corrections to muon anomalous magnetic moment, ${a}_{\ensuremath{\mu}}{=(g}_{\ensuremath{\mu}}\ensuremath{-}2)/2,$ are examined. Short-distance logarithms shown be unaffected. computation long-distance contributions is improved by use an effective field theory approach that preserves chiral properties QCD and accounts for constraints from operator product expansion. Small, previously neglected, contributions, suppressed...
QED, Hadronic, and Electroweak Standard Model contributions to the muon anomalous magnetic moment, a_mu = (g_mu-2)/2, their theoretical uncertainties are scrutinized. The status implications of recently reported 2.6 sigma experiment vs.theory deviation a_mu^{exp}-a_mu^{SM} 426(165) times 10^{-11} discussed. Possible explanations due supersymmetric loop effects with m_{SUSY} \simeq 55 sqrt{tan beta} GeV, radiative mass mechanisms at 1--2 TeV scale other ``New Physics'' scenarios examined.
The universal radiative corrections common to neutron and super-allowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found $+2.467(22)\%$, i.e.~about $2.4\sigma$ larger than the previous evaluation. For comparison, we consider several alternative computational methods. All employ an updated perturbative QCD four-loop Bjorken sum rule (BjSR) defined coupling supplemented with nucleon form factor based Born...
Bosonic two-loop electroweak radiative corrections to the muon's anomalous magnetic moment, ${a}_{\ensuremath{\mu}}\ensuremath{\equiv}\frac{({g}_{\ensuremath{\mu}}\ensuremath{-}2)}{2}$, are presented. We find $\frac{\ensuremath{\Delta}{a}_{\ensuremath{\mu}}^{\mathrm{EW}}(2 \mathrm{loop}\mathrm{bosonic})}{{a}_{\ensuremath{\mu}}^{\mathrm{EW}}(1...
Experimental studies of neutron decay, n→peν[over ¯], exhibit two anomalies. The first is a 8.6(2.1) s, roughly 4σ difference between the average beam measured lifetime, τ_{n}^{beam}=888.0(2.0) and more precise trapped ultracold determination, τ_{n}^{trap}=879.4(6) s. second 5σ pre2002 axial coupling, g_{A}, as in decay asymmetries g_{A}^{pre2002}=1.2637(21), recent, post2002, g_{A}^{post2002}=1.2755(11), where, following UCNA Collaboration division, experiments are classified by date their...
Decay rates of unpolarized top quarks into longitudinally and transversally polarized $W$ bosons are calculated to second order in the strong coupling constant ${\ensuremath{\alpha}}_{s}$. Including finite bottom quark mass electroweak effects, standard model predictions for $W$-boson helicity fractions ${\mathcal{F}}_{L}=0.687(5)$, ${\mathcal{F}}_{+}=0.0017(1)$, ${\mathcal{F}}_{\ensuremath{-}}=0.311(5)$.
We present $O({\ensuremath{\alpha}}_{s}^{2})$ corrections to the cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\gamma}}^{*}\ensuremath{\rightarrow}Q\overline{Q}$ close threshold. assume that energy of reaction is such both perturbative expansion in strong coupling constant ${\ensuremath{\alpha}}_{s}$ and velocity $\ensuremath{\beta}$ heavy quarks can be used. obtain terms...
The two-loop electroweak corrections to the anomalous magnetic moment of muon, generated by fermionic loops, are calculated. An interesting role top quark in anomaly cancellation is observed. New corrections, including terms order $G_\mu \alpha m_t^2$, computed and a class diagrams previously thought vanish found be important. total correction $-(23\pm 3) \times 10^{-11}$ which decreases effects on $g-2$, predicted from one-loop calculations, 12\%. We give an updated theoretical prediction...
Determinations of $|{V}_{ud}|$ and $|{V}_{us}|$ along with their implications for the unitarity test $|{V}_{ud}{|}^{2}+|{V}_{us}{|}^{2}+|{V}_{ub}{|}^{2}=1$ are discussed. The leading two-loop radiative corrections to neutron $\ensuremath{\beta}$ decay evaluated used derive a refined relationship $|{V}_{ud}{|}^{2}{\ensuremath{\tau}}_{n}(1+3{g}_{A}^{2})=4908(4)\text{ }\mathrm{s}$. Employing $|{V}_{ud}|=0.9740(5)$ from superallowed nuclear decays measured lifetime...
Within a systematic approach based on dimensionally regularized nonrelativistic quantum electrodynamics, we derive complete result for the two-loop correction to order ${(\ensuremath{\alpha}∕\ensuremath{\pi})}^{2}{(Z\ensuremath{\alpha})}^{4}$ $g$ factor of an electron bound in $nS$ state hydrogenlike ion. The results obtained significantly improve accuracy theoretical predictions carbon and oxygen ions influence value mass inferred from $g$-factor measurements.
We present a complete three-loop calculation of the electric dipole moment $u$ and $d$ quarks in Standard Model. For quark, more relevant for experimentally important neutron moment, we find cancellations which lead to an order magnitude suppression compared with previous estimates.
We derive an analytic result for the pion pole contribution to light-by-light scattering correction anomalous magnetic moment of muon, a(mu) = (g(mu)-2)/2. Using vector meson dominance model transition form factor, we obtain a(LBL,pi0)mu +56x10(-11).
Quantum chromodynamics (QCD) effects in the semileptonic decay b-->clnu are evaluated to second order coupling constant, O(alpha(s){2}), and several orders expansion quark masses, m{c}/m{b}. Corrections calculated for total rate as well first two moments of lepton energy hadron system distributions. Translated into QED applied muon decay, they decrease its predicted by -0.43 ppm.
We consider the interactions in a mesonic system, referred here to as ‘tetron’, consisting of two heavy quarks and lighter antiquarks (which may still be scale QCD), i.e. generally QaQbq¯cq¯d, study existence bound states below threshold for decay into meson pairs. At small ratio heavier quark masses an expansion parameter arises treatment binding such systems. find that limit where all are so Coulomb-like approximation can applied gluon exchange between them, arise when this is certain...
Two loop electroweak corrections to b --> s gamma decays are computed. Fermion and photonic effects found reduce R = BR(b gamma)/BR(b c e nu) by 8+-2% lead the standard model prediction BR(B X_s gamma)=(3.28 +- 0.30)x10^-4 for inclusive B meson decays. Comparison of R^{theory} =(3.04 0.25)x10^-3(1+0.10rho), where rho is a Wolfenstein CKM parameter, with current experimental average R^{exp}=(2.52+-0.52)x10^-3 gives rho=-1.7+-1.9 which consistent -0.21<rho<0.27 obtained from other K physics...
We present an analytic calculation of the O(m alpha^6) recoil and radiative corrections to energy levels positronium nS states their hyperfine splitting. A complete formula valid is given for spectrum S states. Technical aspects are discussed in detail. Theoretical predictions various intervals compared with experimental results.
We calculate the one- and two-loop corrections of order $\ensuremath{\alpha}{(Z\ensuremath{\alpha})}^{6}$ ${\ensuremath{\alpha}}^{2}{(Z\ensuremath{\alpha})}^{6}$, respectively, to Lamb shift in hydrogenlike systems using formalism nonrelativistic quantum electrodynamics. obtain general results valid for all hydrogenic states with nonvanishing orbital angular momentum normalized difference $S$ states. These involve expectation value local effective operators relativistic Bethe logarithms. The...
One loop electroweak radiative corrections to left-right parity violating M{\o}ller scattering ($e^-e^-\to e^-e^-$) asymmetries are presented. They reduce the standard model (tree level) prediction by 40$\pm 3$ \% where main shift and uncertainty stem from hadronic vacuum polarization loops. A similar reduction also occurs for electron-electron atomic interaction. That effect can be attributed an increase of $\sin^2\theta_W(q^2)$ $3\%$ in running $q^2=m_Z^2$ 0. The sensitivity asymmetry...
Experimental searches for lepton-flavor-violating coherent muon-to-electron conversion in the field of a nucleus, have been proposed to reach unprecedented sensitivity 10^(-16) - 10^(-18) per stopped muon. At that level, they probe new interactions at effective-mass scales well beyond 1000 TeV. However, must contend with background from ordinary bound muon decay. To better understand background-spectrum shape and rate, we carried out detailed analysis Coulombic-bound-state decay, including...
Pion beta decay, ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{e}^{+}\ensuremath{\nu}(\ensuremath{\gamma})$, provides a theoretically clean $\ifmmode\pm\else\textpm\fi{}0.3%$ determination of the Cabibbo-Kobayashi-Maskawa matrix element ${V}_{\mathrm{ud}}$. Although impressive, that result falls short super-allowed nuclear decays where an order magnitude better precision already exists. Here, we advocate new strategy for utilizing pion based on its utility in...
Abstract We analyze the angular momentum balance for a particle undergoing Thomas precession. The relationships among relativistic torque, center of mass, and inertia spinning are clarified. show that spin precession is accompanied by orbital precession, present examples resulting out-of-plane motion.