Is the probability of nding the quark antiquark with

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: e outgoing neutrino is not reconstructed. Thus, experimentally, all of the event information must be inferred from the hadronic shower in that case. Using these variables, the inclusive cross section for DIS scattering of neutrinos and antineutrinos can be written as 2 " d2 ; G2 ME y F ¼ 2xF1 ðx; Q2 Þ 2 =M2 Þ2 2 dxdy ð1 þ Q W;Z   Mxy F2 ðx; Q2 Þ þ 1ÀyÀ 2E    y 2Þ ; (86) Æ y 1 À xF3 ðx; Q 2 i¼u;d;... X " ½xqðx; Q2 Þ À xqðx; Q2 ފ; (89) where RL ðx; Q2 Þ is the ratio of cross sections for scattering off longitudinally and transversely polarized exchange bosons. Measurement of these structure functions has been the focus of many charged lepton and neutrino DIS experiments, which together have probed F2 ðx; Q2 Þ, RL ðx; Q2 Þ, and xF3 (in the case of neutrino scattering) over a wide range of x and Q2 values (Nakamura, K. et al., 2010). Neutrino scattering is unique, however, in that it measures the valence quark distributions through measurement of xF3 and the strange quark distribution through detection of neutrinoinduced dimuon production. These provide important constraints that cannot be obtained from either electron or muon scattering experiments. While Eq. (86) provides a tidy picture of neutrino DIS, additional effects must be included in any realistic description of these processes. The inclusion of lepton masses (Albright and Jarlskog, 1975; Kretzer and Reno, 2002), higher order QCD processes (Moch and Vermaseren, 2000; McFarland and Moch, 2003; Dobrescu and Ellis, 2004), nuclear effects, radiative corrections (Sirlin and Marciano, 1981; Arbuzov et al., 2005; De Rujula, Petronzio, and Savoy-Navarro, 1979; Bardin and Dokuchaeva, 1986; Diener et al., 2004), target mass effects (Schienbein et al., 2008), heavy quark production (Barnett, 1976; Georgi and Politzer, 1976; Gottschalk, 1981), and nonperturbative higher twist effects (Buras, 1980) further modify the scattering kinematics and cross sections. In general, these contributions are typically well known and do not add large uncertainties to the predicted cross sections. Having completed a brief description of DIS, we next turn to some of the experimental measurements. Table XIV lists the most recent experiments that have probed such highenergy neutrino scattering. To isolate DIS events, neutrino experiments typically apply kinematic cuts to remove quasielastic scattering (Sec. V.A) and resonance-mediated (Sec. V.C) contributions from their data. Using high statistics samples of DIS events, these experiments have provided measurements of the weak mixing angle sin2 W from NC where GF is again the Fermi weak coupling constant, MW;Z is the mass of the W Æ (Z0 boson) in the case of CC (NC) scattering, and the þðÀÞ sign in the last term refers to neutrino (antineutrino) interactions. In Eq. (86), Fi ðx; Q2 Þ are the dimensionless nucleon structure functions that encompass the underlying structure of the target. For electron scattering, there...
View Full Document

This document was uploaded on 09/28/2013.

Ask a homework question - tutors are online