arXiv subjects

A. B. Kaidalov

Publications and source records attributed to A. B. Kaidalov.

At least 37 records · Page 2Linked to original sources

arXiv2007

Thermal Dileptons at LHC

We predict dilepton invariant-mass spectra for central 5.5 ATeV Pb-Pb collisions at LHC. Hadronic emission in the low-mass region is calculated using in-medium spectral functions of light vector mesons within hadronic many-body theory. In the intermediate-mass region thermal radiation from the Quark-Gluon Plasma, evaluated perturbatively with hard-thermal loop corrections, takes over. An important source over the entire mass range are decays of correlated open-charm hadrons, rendering the nuclear modification of charm and bottom spectra a critical ingredient.

hep-ph↗

arXiv2007

To the origin of the difference of FSI phases in $B\toππ$ and $B\toρρ$ decays

The final state interactions (FSI) model in which soft rescattering of low mass intermediate states dominates is suggested. It explains why the strong interaction phases are large in the $B_d\toππ$ channel and are considerably smaller in the $B_d\toρρ$ one. Direct CP asymmetries of $B_d\toππ$ decays which are determined by FSI phases are considered as well.

hep-ph↗

arXiv2006

Some Problems of Diffraction at High Energies

An interplay of perturbative and nonperturbative effects in pomeron, odderon and reggeons dynamics is discussed. It is pointed out that experimental data on pion charge exchange reaction at high energies indicate to a dominance of the nonperturbative string-like dynamics up to rather large momentum transfer. Role of shadowing effects related to triple-pomeron interactions is investigated.

hep-ph↗

arXiv2006

$B \to ππ$ decays: branching ratios and CP asymmetries

Theoretically motivated smallness of the penguin amplitude in $B \to ππ$ decays allowes to calculate the value of the unitarity triangle angle $α(ϕ_2)$ with good accuracy. The relatively large branching ratio of the decay into $π^0 π^0$ is explained by the large value of FSI phase difference between $ΔI = 1/2$ and $ΔI = 3/2$ tree amplitudes.

hep-ph↗

arXiv2006

Gluon shadowing in the Glauber-Gribov model

New data from HERA experiment on (diffractive) deep inelastic scattering has been used to parameterize nucleon and Pomeron structure functions. Within the Gribov theory, the parameterizations were employed to calculate gluon shadowing for various heavy ions and compared our results with predictions from other models. Calculations for d+Au collisions at forward rapidities at ultra-relativistic energies have been made and are compared to RHIC data on the nuclear modification factor. Results for gluon shadowing are also confronted with recent data on the nuclear modification factor at $\sqrt{s} = 17.3$ GeV at various values of the Feynman variable $x_F$, and the energy dependence of the effect is discussed.

hep-ph↗

arXiv2006

Leading neutron spectra

It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.

hep-ph↗

arXiv2006

Odderon and Pomeron from the Vacuum Correlator Method

Glueball masses with J<=7 are computed both for C=+1 and C=-1 using the string Hamiltonian derived in the framework of the Vacuum Correlator Method. No fitting parameters are used, and masses are expressed in terms of string tension $σ$ and effective value of $α_s$. We extend the calculations done for J<=3 using the same Hamiltonian, which provided glueball masses in good agreement with existing lattice data, to higher mass states. It is shown that 3^{--}, 5^{--} and 7^{--} states lie on the odderon trajectories with the intercept around or below 0.14. Another odderon trajectory with 3g glueballs of Y-shape, corresponds to 11% higher masses and low intercept. These findings are in agreement with recent experimental data, setting limits on the odderon contribution to the exclusive $γp$ reactions.

hep-ph↗

arXiv2006

Gluon shadowing and unitarity effects

New data from HERA experiment on deep inelastic scattering have been used to parametrize nucleon and Pomeron structure functions. Within the Gribov theory, the parameterizations were employed to calculate gluon shadowing for various heavy ions. The latter was compared with predictions from other models. Calculations of multiplicity reduction due to gluon shadowing for d+Au collisions at forward rapidities at $\sqrt{s}$=200 GeV are in good agreement with BRAHMS data on the nuclear modification factor.

hep-ph↗

arXiv2005

The partonic interpretation of reggeon theory models

We review a physical content of the two simplest models of reggeon field theory: namely the eikonal and the Schwimmer models. The AGK cutting rules are used to obtain the inclusive, the inelastic and the diffractive cross sections. The system of nonlinear equations for these cross sections is written down and analytic expressions for its solution are obtained. We derive the rapidity gap dependence of the differential cross sections for diffractive dissociation in the Schwimmer model and in its eikonalized extension. The results are interpreted from the partonic viewpoint of the interaction at high energies.

hep-ph↗

arXiv2005

Diffractive processes as a tool for searching for new physics

We show that the addition of detectors to tag the outgoing forward protons, at the LHC, will significantly enlarge the potential of studying New Physics. A topical example is Higgs production by the exclusive double-diffractive process, pp -> p+H+p. We discuss the production of Higgs bosons in both the SM and MSSM. We show how the predicted rates may be checked at the Tevatron by observing the exclusive double-diffractive production of dijets, or $χ_c$ or $χ_b$ mesons, or $γγ$ pairs.

hep-ph↗

arXiv2005

Hydrogen atom and one-electron molecular systems in a strong magnetic field: are all of them alike?

Easy physics-inspired approximations of the total and binding energies for the ${\rm H}$ atom and for the molecular ions $${\rm H}_2^{(+)} ({\rm ppe}), {\rm H}_3^{(2+)} ({\rm pppe}), ({\rm HeH})^{++} (\al {\rm p e}), {\rm He}_2^{(3+)} (\al \al {\rm e})$$ as well as quadrupole moment for the ${\rm H}$ atom and the equilibrium distances of the molecular ions in strong magnetic fields $> 10^{9}$ G are proposed. The idea of approximation is based on the assumption that the dynamics of the one-electron Coulomb system in a strong magnetic field is governed by the ratio of transverse to longitudinal sizes of the electronic cloud.

physics.atom-ph↗

arXiv2004

Anomalous suppression of $π^0$ production at large transverse momentum in Au + Au and d + Au collisions at $\sqrt{{\bf s}_{\bf NN}} =$ 200 GeV

We propose a model of suppression of large $p_T$-pions in heavy ion collisions based on the interaction of the large $p_T$ pion with the dense medium created in the collision. The model is practically the same as the one previously introduced to describe $J/ψ$ suppression. Both the $p_T$ and the centrality dependence of the data are reproduced. In deuteron-gold collisions, the effect of the final state interaction with the dense medium turns out to be negligibly small. Here the main features of the data are also reproduced both at mid and at forward rapidities.

hep-ph↗

arXiv2004

Nuclear Shadowing and Diffraction

The relation between diffraction in lepton-proton collisions and shadowing of nuclear structure functions which arises from Gribov inelastic shadowing, is described. A model realizing such relation, which produces a parameter-free description of experimental data on nuclear structure functions at small $x$, is presented. The application to the description of multiplicities in nuclear collisions is discussed and related to other approaches.

hep-ph↗

arXiv2004

Diffractive Higgs production and related processes

We review the signal, and the $b\bar{b}$ background, for Higgs production by the exclusive double-diffractive process, $pp \to p+H+p$, and its subsequent $H \to b\bar{b}$ decay, at the LHC. We discuss the production of Higgs bosons in both the SM and MSSM. We show how the predicted rates may be checked at the Tevatron by observing the exclusive double-diffractiveproduction of dijets, or $χ_c$ or $χ_b$ mesons, or $γγ$ pairs.

hep-ph↗

arXiv2004

Large transverse momentum suppression of $π^0$'s in Au+Au and d+Au collisions at $\sqrt{s}=200$ GeV

We propose a model of suppression of $π^0$'s based on two different effects: at low $p_T$ we take into account the shadowing corrections, while at large $p_T$ the suppression is produced due to the interaction of the large $p_T$ pion with the dense medium created in the collision. The main features of the data on $AuAu$ and $dAu$ collisions are reproduced both at mid and at forward rapidities.

nucl-th↗

arXiv2003

Extending the study of the Higgs sector at the LHC by proton tagging

We show that forward proton tagging may significantly enlarge the potential of studying the Higgs sector at the LHC. We concentrate on Higgs production via central exclusive diffractive processes (CEDP). Particular attention is paid to regions in the MSSM parameter space where the partial width of the Higgs boson decay into two gluons much exceeds the SM case; here the CEDP are found to have special advantages.

hep-ph↗

arXiv2003

Central exclusive diffractive production as a spin--parity analyser: from hadrons to Higgs

We present the general rules for double-Reggeon production of objects with different spins and parities. The existing experimental information on resonance production in these central exclusive diffractive processes is discussed. The absorptive corrections are calculated and found to depend strongly on the quantum numbers of the produced states. The central exclusive diffractive production of 0^+ and 0^- Higgs bosons is studied as an illustrative topical example of the use of the general rules. The signal for diffractive 0^+ and 0^- Higgs production at the LHC is evaluated using, as an example, the minimal supersymmetric model, with large tan(beta).

hep-ph↗

arXiv2003

Nuclear Structure Functions at Small x from Inelastic Shadowing and Diffraction

A model for shadowing in nuclear structure functions at small $x$ and small or moderate $Q^2$ is presented using the relation with diffraction that arises from Gribov's reggeon calculus. A reasonable description of the experimental data is obtained with no fitted parameters. A comparison with predictions from other models is performed.

hep-ph↗