121188774
IDENTIFICATION OF GRAVITON EXCHANGE EFFECTS AT HIGH ENERGY COLLIDERS
121521784
Effects of new neutral currents at linear electron-positron colliders
AbstractEffects that are induced by contact four-fermion interactions in the processes e+e− → μ+μ−, 
$$\bar bb$$
, and 
$$\bar cc$$
 at 
$$\sqrt s = 0.5$$
TeV linear electron-positron colliders are investigated for the case of longitudinally polarized initial beams. This analysis employs new integrated observables constructed from the polarized cross sections for the scattering of final fermions into the forward (σF) and the backward (σB) hemisphere in such a way that they single out the helicity cross sections for the processes in question. This property of the observables makes it possible to perform, in the most general form, a model-independent analysis of contact four-fermion interactions and to set constraints on their parameters. It is also shown that the sensitivity of new polarization observables to contact interactions is noticeably higher than the corresponding sensitivity of canonical observables like σ, AFB, ALR, and ALR,FB.
8525441
Contact interactions and polarized beams at a linear collider
We discuss contact-interaction searches in the processes e + e ! + , b b and c c at an e + e Linear Collider with c.m. energy p s =0 :5 TeV and with longitudinally polarized beams. The measurement of polarized cross sections allows to study the individual helicity cross sections, and consequently to derive separate, model-independent, constraints on the four-fermion contact interaction couplings. We evaluate the reach on those parameters foreseeable in the case of both electron and positron polarization xed at some reference values, and compare it with the situation where only electron polarization is available. The analysis is based on polarized integrated cross sections with optimal kinematical cuts that can improve the sensitivity to the relevant couplings. While electron polarization would by itself allow such an analysis, the additional positron polarization (with no loss of beam intensity) and optimization can have a crucial role in improving the sensitivity to the new interactions.
121870869
Determination of the spin of the narrow graviton Kaluza–Klein resonances in the process of lepton pair production in the Large Hadron Collider for the ATLAS experiment
The method of identifying the spin of the first excited graviton state predicted by the Randall–Sundrum model with additional spatial measurements in the process of lepton pair production in the Large Hadron Collider (LHC) is suggested. The method is based on an analysis of the characteristic angular distributions of the lepton pairs being the graviton decay products. Graviton discovery and identification reaches equal to 2.1 TeV (1.2 TeV) and 3.9 TeV (2.9 TeV) are established with a confidence level of 5σ (95%) for graviton coupling constants $ {{k} \left/ {{{{\bar{M}}_{\text{Pl}}}}} \right.} $ equal to 0.01 and 0.1, respectively, for the ATLAS experiment on the LHC.
119360781
Search for New Physics Effects at a Linear Collider with Polarized Beams
The four-fermion contact-interaction searches in the process $e^+e^-\to\mu^+\mu^-$ at a future $e^+e^-$ Linear Collider with c.m. energy $\sqrt{s}=0.5$ TeV and with both beams longitudinally polarized are studied. We evaluate the corresponding model-independent constraints on the coupling constants, emphasizing the role of beam polarization, and make a comparison with the case of Bhabha scattering.
17588569
Model independent analysis of the trilinear gauge boson couplings at LC: role of polarized cross sections
By means of a model-independent analysis, we discuss the constraints on anomalous trilinear gauge-boson couplings that can be obtained from the study of electron-positron annihilation into $W$ pairs at LC with \sqrt{s}=0.5 TeV and 1 TeV. We consider the general CP conserving anomalous effective Lagrangian, as well as some specific models with reduced number of independent couplings. The analysis is based on combinations of observables with initial and final state polarizations, that allow to separately constrain the different couplings and to improve the corresponding numerical bounds.
120719997
Search for astrophysical neutrinos in the Baikal neutrino project
The currently running NT200 and NT200+ Baikal neutrino telescopes and the prospects for development of the Baikal Neutrino Project are briefly descr⇊ed. Preliminary results of the search for neutrino events correlated with cosmological gamma-ray bursts at the NT200 are presented. The feasibility of developing a method for acoustic detection of ultrahigh-energy neutrinos in the Baikal Neutrino Project is discussed. The calculation results for the energy spectrum and zenith-angle distributions of atmospheric neutrinos in the energy range from 10 to 107 GeV obtained within various high-energy hadron-nucleus interaction models are presented.