118879924
Sneutrino identification in lepton pair production at ILC with polarized beams
Abstract Numerous non-standard dynamics are described by contact-like effective interactions that can manifest themselves in electron–positron collisions only through deviations of the observables (cross sections, asymmetries) from the Standard Model predictions. If such a deviation were observed, it would be important to identify the actual source among the possible non-standard interactions as many different new physics scenarios may lead to very similar experimental signatures. We study the possibility of uniquely identifying the indirect effects of s -channel sneutrino exchange, as predicted by supersymmetric theories with R -parity violation, against other new physics scenarios in high-energy e + e − annihilation into lepton pairs at the International Linear Collider. These competitive models are interactions based on gravity in large and in TeV-scale extra dimensions, anomalous gauge couplings, Z ′ vector bosons and compositeness-inspired four-fermion contact interactions. To evaluate the identification reach on sneutrino exchange, we use as basic observable a double polarization asymmetry, that is particularly suitable to directly test for such s -channel sneutrino exchange effects in the data analysis. The availability of both beams being polarized plays a crucial role in identifying the new physics scenario.
18700563
Probing three boson anomalous coupling in e+ e- ----> W+ W- at future linear e+ e- colliders with polarized beams
We study the potential of the next-generation $e^+ e^-$ linear colliders with longitudinally polarized beams, to restrict the values of the anomalous trilinear couplings $WW\gamma$ and $WWZ$ from the measurement of the process $e^+ e^-\to W^+ W^-$. Along with initial $e^+e^-$ polarization, we account also for the possibilities offered by cross sections for polarized final $W$, in order to disentangle the constraints on the various constants. The results show the essential role of the initial beams polarization in improving the bounds obtained from the unpolarized case.
204940702
New Physics Effects in Fermion-Pair Production at e+e− Colliders
Fermion compositeness, and other types of new physics that can be described by the exchange of very massive particles, can manifest themselves as the result of an effective four-fermion contact interaction. In the case of the processes e+e− → μ+μ−, τ+τ−, b̄b and c̄c at future e+e− colliders with √s = 0.5 − 1 TeV, we examine the sensitivity to four-fermion contact interactions of two new integrated observables, σ+ and σ−, conveniently defined for such kind of analysis. We find that, if longitudinal polarization of the electron beam were available, these observables would offer the opportunity to separate the helicity cross sections and, in this way, to derive model-independent bounds on the relevant parameters.
121188774
IDENTIFICATION OF GRAVITON EXCHANGE EFFECTS AT HIGH ENERGY COLLIDERS
17667398
Model independent constraints on contact interactions from polarized Bhabha scattering at LC
We discuss electron-electron contact-interaction searches in the process e^+e^- -->e^+e^- at a future e^+e^- Linear Collider with c.m. energy \sqrt{s}=0.5 TeV and with both beams longitudinally polarized. Our analysis is based on the measurement of the polarized differential cross sections, and allows to simultaneously take into account the general set of contact interaction couplings as independent, non-zero, parameters thus avoiding simplifying, model-dependent, assumptions. 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 e^+e^- -->\mu^+\mu^-.
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.
120988003
Baikal neutrino project: history and prospects
The history, current status, and prospects for the development of the Baikal Neutrino Project are considered. The main physical results obtained with the help of NT200 and NT200+ neutrino telescopes are presented.
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.
122314224
The Gigaton Volume Detector in Lake Baikal
Abstract The objective of the Baikal Project is the creation of a kilometer-scale high-energy neutrino observatory: the Gigaton Volume Detector (GVD) in Lake Baikal. Basic elements of the GVD – new optical modules, FADC readout units, and underwater communication systems – were investigated and tested in Lake Baikal with prototype strings in 2008–2010. We describe the results of prototype strings operation and review the preliminary design and expected sensitivity of the GVD telescope.