ترغب بنشر مسار تعليمي؟ اضغط هنا

Discriminating Z from anomalous trilinear gauge coupling signatures in e+e- to W+W- at ILC with polarized beams

128   0   0.0 ( 0 )
 نشر من قبل Per Osland
 تاريخ النشر 2012
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

New heavy neutral gauge bosons Z are predicted by many models of physics beyond the Standard Model. It is quite possible that Zs are heavy enough to lie beyond the discovery reach of the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z exchanges may emerge at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We discuss in this context the foreseeable sensitivity to Zs of W^pm-pair production cross sections at the e^+e^- International Linear Collider (ILC), especially as regards the potential of distinguishing observable effects of the Z from analogous ones due to competitor models with anomalous trilinear gauge couplings (AGC) that can lead to the same or similar new physics experimental signatures at the ILC. The sensitivity of the ILC for probing the Z-Z mixing and its capability to distinguish these two new physics scenarios is substantially enhanced when the polarization of the initial beams and the produced W^pm bosons are considered. A model independent analysis of the Z effects in the process e^+e^- to W^+W^- allows to differentiate the full class of vector Z models from those with anomalous trilinear gauge couplings, with one notable exception: the sequential SM (SSM)-like models can in this process not be distinguished from anomalous gauge couplings. Results of model dependent analysis of a specific Z are expressed in terms of discovery and identification reaches on the Z-Z mixing angle and the Z mass.



قيم البحث

اقرأ أيضاً

In this work, Higgs couplings with gauge bosons is probed through $e^-e^+ rightarrow W^-W^+H$ in an effective Lagrangian framework. An ILC of 500 $GeV$ center of mass energy with possible beam polarization is considered for this purpose. The reach of ILC with integrated luminosity of 300 $fb^{-1}$ in the determination of both the CP-conserving and CP-violating parameters are obtained. Sensitivity of the probe of each of these couplings on the presence of other couplings is investigated. The most influential couplings parameters are $bar c_W=-bar c_B$. Other parameters of significant effect are $bar c_{HW}$ and $bar c_{HB}$ among the CP-conserving ones, and $tilde c_{HW}$ and $tilde c_{HB}$ among the CP-violating ones. CP-violating parameter, $tilde c_gamma$ seems to have very little influence on the process considered. Detailed study of the angular distributions have presented a way to disentangle the effect of some of these couplings.
The anomalous $WWgamma$ coupling is probed through $egammarightarrow u W$ at the ILC. With a spectacular single lepton final state, this process is well suited to study the above coupling. Cross section measurements can probe $delta kappa_gamma$ to about $pm 0.004$ for a luminosity of 100 fb$^{-1}$ at $500$ GeV center-of-mass energy with unpolarized electron beam. The limits derivable on $lambda_gamma$ from the total cross section are comparatively more relaxed. Exploiting the energy-angle double distribution of the secondary muons, kinematic regions sensitive to these couplings are identified. The derivable limit on $lambda_gamma < 0$ could be improved to a few per-mil, focusing on such regions. More importantly, the angular distributions at fixed energy values, and energy distribution at fixed angles present very interesting possibility of distinguishing the case of $lambda_gamma <0$ and $lambda_gamma ge 0$.
We investigate selectron pair production and decay in e-e- scattering and e+e- annihilation with polarized beams taking into account neutralino mixing as well as ISR and beamstrahlung corrections. One of the main advantages of having both modes at di sposal is their complementarity concerning the threshold behaviour of selectron pair production. In e-e- the cross sections at threshold for seleectron_R selectron_R and selectron_L selectron_L rise proportional to the momentum of the selectron and in e+ e- that for selectron_R selectron_L. Measurements at threshold with polarized beams can be used to determine the selectron masses precisely. Moreover we discuss how polarized electron and positron beams can be used to establish directly the weak quantum numbers of the selectrons. We also use selectron pair production to determine the gaugino mass parameter M_1. This is of particular interest for scenarios with non-universal gaugino masses at a high scale resulting in |M_1| << |M_2| at the electroweak scale. Moreover, we consider also the case of a non-vanishing selectron mixing and demonstrate that it leads to a significant change in the phenomenology of selectrons.
We explore the effects of neutrino and electron mixing with exotic heavy leptons in the process e^+e^-to W^+W^- within E_6 models. We examine the possibility of uniquely distinguishing and identifying such effects of heavy neutral lepton exchange fro m Z-Z mixing within the same class of models and also from analogous ones due to competitor models with anomalous trilinear gauge couplings (AGC) that can lead to very similar experimental signatures at the e^+e^- International Linear Collider (ILC) for sqrt{s}=350, 500 GeV and 1 TeV. Such clear identification of the model is possible by using a certain double polarization asymmetry. The availability of both beams being polarized plays a crucial role in identifying such exotic-lepton admixture. In addition, the sensitivity of the ILC for probing exotic-lepton admixture is substantially enhanced when the polarization of the produced W^pm bosons is considered.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا