arXiv subjects

A. Kurylov

Publications and source records attributed to A. Kurylov.

10 recordsLinked to original sources

arXiv2004

Neutrinoless Double Beta Decay and Lepton Flavor Violation

We point out that extensions of the Standard Model with low scale (~TeV) lepton number violation (LNV) generally lead to a pattern of lepton flavor violation (LFV) experimentally distinguishable from the one implied by models with GUT scale LNV. As a consequence, muon LFV processes provide a powerful diagnostic tool to determine whether or not the effective neutrino mass can be deduced from the rate of neutrinoless double beta decay. We discuss the role of μ-> e γand μ-> e conversion in nuclei, which will be studied with high sensitivity in forthcoming experiments.

hep-ph↗

arXiv2004

Lepton Flavor Violation without Supersymmetry

We study the lepton flavor violating (LFV) processes mu -> e gamma, mu -> 3e, and mu -> e conversion in nuclei in the left-right symmetric model without supersymmetry and perform the first complete computation of the LFV branching ratios B(mu -> f) to leading non-trivial order in the ratio of left- and right-handed symmetry breaking scales. To this order, B(mu -> e gamma) and B(mu -> e) are governed by the same combination of LFV violating couplings, and their ratio is naturally of order unity. We also find B(mu -> 3 e)/B(mu -> e) \sim 100 under slightly stronger assumptions. Existing limits on the branching ratios already substantially constrain mass splittings and/or mixings in the heavy neutrino sector. When combined with future collider studies and precision electroweak measurements, improved limits on LFV processes will test the viability of low-scale, non-supersymmetric LFV scenarios.

hep-ph↗

arXiv2003

Probing Supersymmetry with Neutral Current Scattering Experiments

We compute the supersymmetric contributions to the weak charges of the electron and proton in the framework of Minimal Supersymmetric Standard Model. We also consider the ratio of neutral current to charged current cross sections, R_nu and R_nubar at nu (nubar)-nucleus deep inelastic scattering, and compare the supersymmetric corrections with the deviations of these quantities from the Standard Model predictions implied by the recent NuTeV measurement.

hep-ph↗

arXiv2003

Supersymmetric Effects in Parity-Violating Deep Inelastic Electron-Nucleus Scattering

We compute the supersymmetric (SUSY) corrections to the parity-violating, deep inelastic electron-deuteron asymmetry. Working with the Minimal Supersymmetric Standard Model (MSSM) we consider two cases: R parity conserving and R parity-violating. Under these scenarios, we compare the SUSY effects with those entering other parity-violating observables. For both cases of the MSSM, we find that the magnitude of the SUSY corrections can be as large as about 1% and that they are strongly correlated with the effects on other parity-violating observables. A comparison of various low-energy parity-violating observables thus provides a potentially interesting probe of SUSY.

hep-ph↗

arXiv2003

Supersymmetric Effects in Deep Inelastic Neutrino-Nucleus Scattering

We compute the supersymmetric (SUSY) contributions to neutrino (antineutrino)-nucleus deep inelastic scattering in the Minimal Supersymmetric Standard Model (MSSM). We consider the ratio of neutral current to charged current cross sections, $R_ν$ and $R_{\bar ν}$, and compare with the deviations of these quantities from the Standard Model predictions implied by the recent NuTeV measurement. After performing a model-independent analysis, we find that SUSY loop corrections generally have the opposite sign from the NuTeV anomaly. We discuss one scenario in which a right-sign effect arises, and show that it is ruled out by other precision data. We also study for R parity-violating (RPV) contributions. Although RPV effects could, in principle, reproduce the NuTeV anomaly, such a possibility is also ruled out by other precision electroweak measurements.

hep-ph↗

arXiv2002

Radiative corrections to low energy neutrino reactions

We show that the radiative corrections to charged current (CC) nuclear reactions with an electron(positron) in the final state are described by a universal function. The consistency of our treatment of the radiative corrections with the procedure used to extract the value of the axial coupling constant $g_A$ is discussed. To illustrate we apply our results to (anti)neutrino deuterium disintegration and to $pp$ fusion in the sun. The limit of vanishing electron mass is considered, and a simple formula valid for $E_{obs}\gsim 1$ MeV is obtained. The size of the nuclear structure-dependent effects is also discussed. Finally, we consider CC transitions with an electron(positron) in the initial state and discuss some applications to electron capture reactions.

hep-ph↗

arXiv2002

Parity-Violating Electron Scattering as a Probe of Supersymmetry

We compute the one-loop supersymmetric (SUSY) contributions to the weak charges of the electron ($Q_W^e$) and proton ($Q_W^p$) using the Minimal Supersymmetric Standard Model (MSSM). These $q^2=0$ vector couplings of the $Z^0$-boson to fermions will be determined in two fixed-target, parity-violating electron scattering experiments. The SUSY loop contributions to $Q_W^p$ and $Q_W^e$ can be substantial, leading to several percent corrections to the Standard Model values for these quantities. We show that the relative signs of the SUSY loop effects on $Q_W^e$ and $Q_W^p$ are correlated and positive over nearly all of the MSSM parameter space, whereas inclusion of R-parity nonconserving interactions can lead to opposite sign relative shifts in the weak charges. Thus, a comparison of $Q_W^p$ and $Q_W^e$ measurements could help distinguish between different SUSY scenarios.

hep-ph↗

arXiv2001

Radiative corrections in neutrino-deuterium disintegration

The radiative corrections of order $α$ for the charged and neutral current neutrino-deuterium disintegration for energies relevant to the SNO experiment are evaluated. Particular attention is paid to the issue of the bremsstrahlung detection threshold. It is shown that the radiative corrections to the total cross section for the charged current reaction are independent of that threshold, as they must be for consistency, and amount to a slowly decreasing function of the neutrino energy $E_ν$, varying from $\sim$ 4% at low energies to $\sim$ 3% at the end of the $^8$B spectrum. The differential cross section corrections, on the other hand, do depend on the bremsstrahlung detection threshold. Various choices of the threshold are discussed. It is shown that for a realistic choice of the threshold, and for the actual electron energy threshold of the SNO detector, the deduced $^8$B $ν_e$ flux should be decreased by $\sim$ 2%. The radiative corrections to the neutral current reaction are also evaluated.

nucl-th↗

arXiv2001

Charged Current Universality in the MSSM

We compute the complete one-loop contributions to low-energy charged current weak interaction observables in the Minimal Supersymmetric Standard Model (MSSM). We obtain the constraints on the MSSM parameter space which arise when precision low-energy charged current data are analyzed in tandem with measurements of the muon anomaly. While the data allow the presence of at least one light neutralino, they also imply a pattern of mass splittings among first and second generation sleptons and squarks which contradict predictions of widely used models for supersymmetry breaking mediation.

hep-ph↗

arXiv2000

Constraints on T-Odd, P-Even Interactions from Electric Dipole Moments

We construct the relationship between nonrenormalizable,effective, time-reversal violating (TV) parity-conserving (PC) interactions of quarks and gauge bosons and various low-energy TVPC and TV parity-violating (PV) observables. Using effective field theory methods, we delineate the scenarious under which experimental limits on permanent electric dipole moments (EDM's) of the electron, neutron, and neutral atoms as well as limits on TVPC observables provide the most stringent bounds on new TVPC interactions. Under scenarios in which parity invariance is restored at short distances, the one-loop EDM of elementary fermions generate the most severe constraints. The limits derived from the atomic EDM of $^{199}$Hg are considerably weaker. When parity symmetry remains broken at short distances, direct TVPC search limits provide the least ambiguous bounds. The direct limits follow from TVPC interactions between two quarks.

hep-ph↗