Cannot be directly compared with this historical data

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Unformatted text preview: pþ Þ ð p !  p0 Þ=ð p ! À pþ Þ ð p !  nþ Þ=ð p ! À pþ Þ ð p !  nþ Þ=ð p ! À pþ Þ ð n !  pÀ Þ=ð n ! À nþ Þ ð N !  N0 Þ=2ð n ! À p0 Þ ð N !  N0 Þ=2ð n ! À p0 Þ ð N !  N0 Þ=2ð n ! À p0 Þ ð N !  N0 Þ=2ð n ! À p0 Þ ð n !  pÀ Þ=ð p ! À pþ Þ 0:51 Æ 0:25 0:09 Æ 0:05a 0:17 Æ 0:08 0:12 Æ 0:04 0:38 Æ 0:11 0:45 Æ 0:08 0:40 Æ 0:06 0:17 Æ 0:04 0:25 Æ 0:09b 0:11 Æ 0:022 (Barish et al., 1974) (Derrick et al., 1981) (Barish et al., 1974) (Derrick et al., 1981) (Fogli and Nardulli, 1980) (Krenz et al., 1978a) (Fogli and Nardulli, 1980) (Lee et al., 1977) (Nienaber, 1988) (Derrick et al., 1981) a In their later paper (Derrick et al., 1981), Derrick et al. remark that while this result is 1:6 smaller than their previous result (Barish et al., 1974), the neutron background was later better understood. b The BNL NC 0 data (Lee et al., 1977) were later reanalyzed after properly taking into account multipion backgrounds and found to have a larger fractional cross section (Nienaber, 1988). Aachen, PL 125B, 230 (1983), Al (10-38 cm2 / nucleon) 0.25 GGM, NP B135, 45 (1978), C H8 CF3Br 3 0.2 NUANCE (M =1.1 GeV) A 0.15 0) 0.25 Aachen, PL 125B, 230 (1983), Al 0.2 NUANCE (M =1.1 GeV) A 0.15 µ p 0.1 1 10 2 ( E (GeV) FIG. 16. Existing measurements of the cross section for the NC process,  p !  p0 , as a function of neutrino energy. Also shown is the prediction from Casper (2002) assuming MA ¼ 1:1 GeV. The Gargamelle measurement comes from a more recent reanalysis of these data. Modern measurements (Table XII) exist but cannot be directly compared with this historical data. From Hawker, 2002. Rev. Mod. Phys., Vol. 84, No. 3, July–September 2012 0.05 10 p 0 µ µp 0.1 0.05 ( µp experiments have realized the importance of final-state effects, often directly reporting the distributions of final-state particles they observe. Such ‘‘observable’’ cross sections are more useful in that they measure the combined effects of nuclear processes and are much less model dependent. Table XII lists the collection of some of these most recent pion production cross section reportings. Measurements have been produced in the form of both ratios and absolute cross sections, all on carbon-based targets. Similar measurements on additional nuclear targets are clearly needed to help round out our understanding of nuclear effects in pion production interactions. Before we move on, it should be noted that many of the same baryon resonances that decay to single pion final states can also decay to photons (e.g., Á ! N and N Ã ! N ). Such radiative decay processes have small branching fractions (<1%) yet, like NC 0 production, they still pose nonnegligible sources of background to  ! e oscillation searches. There have been no direct experimental measurements of neutrino-induced resonance radiative decay to date; however, studi...
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This document was uploaded on 09/28/2013.

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