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V. Petrov

Publications and source records attributed to V. Petrov.

26 records · Page 2Linked to original sources
arXiv2004

Optical, vibrational, thermal, electrical, damage and phase-matching properties of lithium thioindate

Lithium thioindate (LiInS$_{2}$) is a new nonlinear chalcogenide biaxial material transparent from 0.4 to 12 $μ$m, that has been successfully grown in large sizes and good optical quality. We report on new physical properties that are relevant for laser and nonlinear optics applications. With respect to AgGaS(e)$_2$ ternary chalcopyrite materials, LiInS$_{2}$ displays a nearly-isotropic thermal expansion behavior, a 5-times larger thermal conductivity associated with high optical damage thresholds, and an extremely low intensity-dependent absorption allowing direct high-power downconversion from the near-IR to the deep mid-IR. Continuous-wave difference-frequency generation (5-11$ μ$m) of Ti:sapphire laser sources is reported for the first time.

physics.optics↗
arXiv2004

Search for Squark Production in R-Parity Violating Supersymmetry at HERA

A search for squarks in R-parity violating supersymmetry is performed in e+/- p collisions at HERA using the H1 detector. The data were taken at a centre-of-mass energy of 319 GeV and correspond to an integrated luminosity of 64.3 pb-1 for e+p collisions and 13.5 pb-1 for e-p collisions. The resonant production of squarks via a Yukawa coupling lambda' is considered, taking into account direct and indirect R-parity violating decay modes. No evidence for squark production is found in the multi-lepton and multi-jet final state topologies investigated. Mass dependent limits on lambda' are obtained in the framework of the Minimal Supersymmetric Standard Model. In addition, the results are interpreted in terms of constraints on the parameters of the minimal Supergravity model. At the 95% confidence level squarks of all flavours with masses up to 275 GeV are excluded in a large part of the parameter space for a Yukawa coupling of electromagnetic strength. For a coupling strength 100 times smaller, masses up to 220 GeV can be ruled out.

hep-ex↗
arXiv2002

Spontaneously Broken Chiral Symmetry and Hard QCD Phenomena

These are the mini-proceedings of the workshop ``Spontaneously Broken Chiral Symmetry and Hard QCD Phenomena" held at the Physikzentrum Bad Honnef from July 15 to 19, 2002. Every author presents a summary of his talk. The transparencies of all speakers and further information on the workshop can be found on the website: http://www.tp2.ruhr-uni-bochum.de/hardreactions.html

hep-ph↗
arXiv2001

Resonant mesomolecule formation

The dtm and ddm resonant fusion rates are calculated taking into account finite resonance width and subthreshold resonances. Calculations do not use multipole expansion of the potential. The obtained ddm resonant fusion rates are compared with recent data at 30-360 K.

nucl-th↗
arXiv1996

Nucleon Parton Distributions at Low Normalization Point in the Large N_c Limit

At large N_c the nucleon can be viewed as a soliton of the effective chiral lagrangian. This picture of nucleons allows a consistent nonperturbative calculation of the leading-twist parton distributions at a low normalization point. We derive general formulae for the polarized and unpolarized distributions (singlet and non-singlet) in the chiral quark-soliton model. The consistency of our approach is demonstrated by checking the baryon number, isospin and total momentum sum rules, as well as the Bjorken sum rule. We present numerical estimates of the quark and antiquark distributions and find reasonable agreement with parametrizations of the data at a low normalization point. In particular, we obtain a sizeable fraction of antiquarks, in agreement with the phenomenological analysis.

hep-ph↗
arXiv1993

$1/N_c$ Rotational Corrections to $g_A$ and Isovector Magnetic Moment of the Nucleon

The $1/N_c$ rotational corrections to the axial vector constant and the isovector magnetic moment of the nucleon are studied in the Nambu -- Jona-Lasinio model. We follow a semiclassical quantization procedure in terms of path integrals in which we can include perturbatively corrections in powers of angular velocity $Ω\sim \frac 1{N_c}$. We find non-zero $1/N_c$ order corrections from both the valence and the Dirac sea quarks. These corrections are large enough to resolve the long-standing problem of a strong underestimation of both $g_A$ and $μ^{IV}$ in the leading order. The axial constant $g_A$ is well reproduced, whereas the isovector magnetic moment $μ^{IV}$ is still underestimated by 25 \%.

hep-ph↗
arXiv1993

Non-Perturbative Isotropic Multi-Particle Production in Yang--Mills Theory

We use singular Euclidean solutions to find multi-particle production cross sections in field theories. We investigate a family of time-dependent O(3) symmetrical solutions of the Yang--Mills equations, which govern the isotropic high-energy gauge boson production. At low energies our approach reproduces the instanton-induced cross sections. For higher energies we get new results. In particular, we show that the cross section for isotropic multiparticle production remains exponentially small in the running gauge coupling constant. The result applies both to the baryon number violation in the electro-weak theory and to the QCD jet production. We find that the isotropic multi-gluon production cross section falls off approximately as a ninth power of energy but possibly might be observable

hep-ph↗