اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدWeak Kaon Production off the nucleon and Watsons theorem
234
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We have improved the tree-level model of Ref arXiv:1004.5484 [hep-ph] for weak production of kaons off nucleons by partially restoring unitarity. This is achieved by imposing Watsons theorem to the dominant vector and axial-vector contributions in appropriate angular momentum and isospin quantum number sectors. The observable consequences of this procedure are investigated.
قيم البحث
اقرأ أيضاً
The weak kaon production off the nucleon induced by neutrinos is studied at the low and intermediate energies of interest for some ongoing and future neutrino oscillation experiments. This process is also potentially important for the analysis of pro
ton decay experiments. We develop a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are fpi, the pion decay constant, Cabibbos angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet, D and F, that are obtained from the analysis of the semileptonic decays of neutron and hyperons. The studied mechanisms are the main source of kaon production for neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross sections are large enough to be amenable to be measured by experiments such as Minerva and T2K.
We present a new determination of the $NDelta$ axial form factors from neutrino induced pion production data. For this purpose, the model of Hernandez {it et al.} [Phys. Rev. D76, 033005 (2007)] is improved by partially restoring unitarity. This is a
ccomplished by imposing Watsons theorem on the dominant vector and axial multipoles. As a consequence, a larger $C_5^A(0)$, in good agreement with the prediction from the off-diagonal Goldberger-Treiman relation, is now obtained.
The strange particle production induced by (anti)neutrino off nucleon has been studied for $|Delta S|=0$ and $|Delta S|=1$ channels. The reactions those we have considered are for the production of single kaon/antikaon, eta and associated particle
production processes. We have developed a microscopical model based on the SU(3) chiral Lagrangian. The basic parameters of the model are $f_pi$, the pion decay constant, Cabibbo angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet. For antikaon production we have also included $Sigma^*$(1385) resonance and for eta production $S_{11}$(1535) and $S_{11}$(1650) resonances are included.
The electromagnetic kaon production amplitudes associated to Lambda/Sigma hyperons can be described by phenomenological models, most notably by isobar approaches. Experimental data on kaon production have been collected at ELSA, SPring8, GRAAL, LNS T
ohoku, and Jefferson Lab in the past, the measurements at Jefferson Lab providing the largest kinematic coverage and statistical significance. However, ambiguities inherent in the models, some data inconsistency in the cross-sections taken at different laboratories, and the problem of missing acceptance in forward direction of the experimental set-ups hinders a reliable extraction of resonance parameters. Predictions for the hypernuclear photo-production cross-section rely on a consistent and comprehensive description of the elementary process at forward kaon angles, where the current strong variation of the models is very unsatisfactory. A number of new experiments are now addressing these issues, among them the charged kaon electro-production programme with the Kaos spectrometer at the Mainz Microtron MAMI. In this work predictions of the two prominent isobar models, Kaon-Maid and Saclay-Lyon A, are compared for the kinematics at MAMI.
Weak pion production off the nucleon at low energies has been systematically investigated in manifestly relativistic baryon chiral perturbation theory with explicit inclusion of the $Delta$(1232) resonance. Most of the involved low-energy constants h
ave been previously determined in other processes such as pion-nucleon elastic scattering and electromagnetic pion production off the nucleon. For numerical estimates, the few remaining constants are set to be of natural size. As a result, the total cross sections for single pion production on neutrons and protons, induced either by neutrino or antineutrino, are predicted. Our results are consistent with the scarce existing experimental data except in the $ u_mu nto mu^-npi^+$ channel, where higher-order contributions might still be significant. The $Delta$ resonance mechanisms lead to sizeable contributions in all channels, especially in $ u_mu pto mu^- ppi^+$, even though the considered energies are close to the production threshold. The present study provides a well founded low-energy benchmark for phenomenological models aimed at the description of weak pion production processes in the broad kinematic range of interest for current and future neutrino-oscillation experiments.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
