Download or read book Search for the Flavor changing Neutral Current Decay K Sup Yields Pi Sup Nu Nu written by and published by . This book was released on 1990 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observation that flavor-changing neutral currents (FCNC) in weak decays are highly suppressed was first explained by Glashow, Iliopoulos and Maiani in 1970, and their idea has since become a cornerstone of the Standard Model. They proposed a model of the weak interaction that included a then new fourth quark and which, in a natural way, allowed the existence of a neutral vector boson without inducing FCNC's at tree level. Thus the couplings of the neutral intermediary{hor ellipsis}cause no embarrassment.'' In higher order through, decays like K →?l{bar l} can proceed. Measurements of such processes provide a detailed test of the Standard Model since definite predictions for their rates can be calculated. Conversely, if no contradictions are found and the standard model is assumed to describe the physics, measurements limit the allowed values of the parameters of the model. As is often the case in studying processes that are highly suppressed and heretofore unseen, improvements in the sensitivity of experiments allow the possibility for the discovery of new physics that exhibits a similar experimental signature. This paper describes experiment 787 at Brookhaven which is expected to address some of these issues. The status and future of the experiment will be described here. The main goal of E787 is to measure the rate of K →?+?{bar {nu}} at the standard model level. In addition, the experiment has sensitivity to other FCNC decays of the charged kaon, in particular the decays K+ →?+?+?− and K+ →?+??
Download or read book SEARCH FOR THE RARE KAON DECAY K sup yields pi sup nu bar nu written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the search for the rare decay K[sup+][yields][pi][sup+][nu][bar[nu]] in the pion momentum region 140 MeV/c[le] P[sub[pi][sup+]][le] 195 MeV/c. This is a Flavor Changing Neutral Current (FCNC) decay which is forbidden to the first order in the Standard Model (SM) by the GIM mechanism. However, this decay mode is allowed in the second order by two Z-Penguin and one box diagram and is expected to have a branching ratio of (0.72[+-] 0.21) x 10[sup -10]. This decay mode is sensitive to the coupling of top to down quark and therefore a measurement of the branching ratio for this decay mode provides a measurement of the Cabibbo-Kobayashi-Maskawa matrix element V[sub td]. The recent observation of two events in the pion momentum region 211 MeV/c[le] P[sup[pi][sup+]][le] 229 MeV/c estimates a branching ratio of 1.57[sub -0.82][sup+1.75] x 10[sup -10] for the same decay mode. We have extended the search for this decay to the lower pion momentum region. Data collected by the Experiment E787 at Brookhaven National Laboratory during the 1996 and 1997 run were analyzed in this thesis.
Download or read book g om trie variable written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1990 with total page 1608 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for D sup yields pi sup mu sup mu sup minus written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Flavor-changing neutral current decays are forbidden in lowest order in the Standard Model. The authors present results of a search for the charm changing neutral current decay D[sup +] [yields] [pi][sup +][mu][sup +][mu][sup [minus]] based on the analysis of one third of the data from Fermilab experiment E791, accumulated during the 1991--92 fixed target run with a 500 GeV negative pion beam incident on a segmented target. Assuming that the decay kinematics are the same as for D[sup +] [yields] K[sup [minus]][pi][sup +][pi][sup +], they set an upper limit on the branching ratio for this channel, B(D[sup +] [yields] [pi][sup +][mu][sup +][mu][sup [minus]])
Download or read book Energy Research Abstracts written by and published by . This book was released on 1989 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The K sub L yields pi sup 0 nu anti nu Decay Beyond the Standard Model written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The K[sub L][yields][pi][sup 0][nu][anti[nu]] decay is analyzed in a model independent way. When lepton flavor is conserved, this decay mode is a manifestation of CP violating interference between mixing and decay. Consequently, a theoretically clean relation between the measured rate and electroweak parameters holds in any given model.
Download or read book Search for Flavor changing Neutral Current and Lepton flavor Violating Decays of D sup 0 ell sup ell sup written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors report on a search for the flavor-changing neutral current decays D[sup 0] --> e[sup +]e[sup -] and D[sup 0] --> [mu][sup +][mu][sup -], and the lepton-flavor violating decay D[sup 0] --> e[sup [+-]][mu][sup [-+]]. The measurement is based on 122 fb[sup -1] of data collected by the BABAR detector at the PEP-II asymmetric e[sup +]e[sup -] collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90% confidence level, are 1.2 x 10[sup -6] for D[sup 0] --> e[sup +]e[sup -], 1.3 x 10[sup -6] for D[sup 0] --> [mu][sup +][mu][sup -], and 8.1 x 10[sup -7] for D[sup 0] --> e[sup [+-]][mu][sup [-+]].
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1995 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flavor Changing Kaon Decays from Hypercp Measurements of the K Pi Mu Mu Branching Ratios written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fermilab HyperCP collaboration is making precision studies of charged hyperon and kaon decays, as well as searches for rare and forbidden hyperon and kaon decays. We report here on measurements of the branching ratios of the flavor-changing neutral-current decays: K[sup[+-]][yields][pi][sup[+-]][mu][sup+][mu][sup -], and compare our results to theoretical predictions. This is the first observation of the K[sup -][yields][pi][sup -][mu][sup+][mu][sup -] decay.
Download or read book Search for Flavor changing Neutral Current and Lepton flavor Violating Decays of D L L written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors report on a search for the flavor-changing neutral current decays D° --> ee− and D° -->?+?−, and the lepton-flavor violating decay D° --> e{sup {+-}}?{sup {-+}}. The measurement is based on 122 fb−1 of data collected by the BABAR detector at the PEP-II asymmetric e+e− collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90% confidence level, are 1.2 x 10−6 for D° --> e+e−, 1.3 x 10−6 for D° -->?+?−, and 8.1 x 10−7 for D° --> e{sup {+-}}?{sup {-+}}.
Download or read book Search for the Decay K sub L 0 Yields Pi sup 0 e e written by and published by . This book was released on 1990 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for the Flavor Changing Neutral Current Decay T Zq at the Square Root Of S written by Jennifer Lindsay Gimmell and published by . This book was released on 2009 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for the Decay K Sub L Sup 0 Yields Pi Sup 0 E Sup E Sup Minus written by and published by . This book was released on 1990 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented of a recent search by AGS Experiment 845 for the CP violating decay K{sub L}° →?°ee−. The 90% C.L. limit B(K{sub L}° →?°e+e−)
Download or read book Lepton flavor Mixing and K Pi Nu Nubar Decays written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of possible sources of lepton-flavor mixing on K [yields] [pi][nu][bar [nu]] decays is analyzed. At the one-loop level lepton-flavor mixing originated from non-diagonal lepton mass matrices cannot generate a CP-conserving K[sub L] [yields] [pi][sup 0][nu][bar [nu]] amplitude. The rates of these modes are sensitive to leptonic flavor violation when there are at least two different leptonic mixing matrices. New interactions that violate both quark and lepton universalities could enhance the CP-conserving component of [Lambda] (K[sub L] [yields] [pi][sup 0][nu][bar [nu]]) and have a substantial impact. Explicit examples of these effects in the context of supersymmetric models, with and without R-parity conservation, are discussed.
Download or read book Stars as Laboratories for Fundamental Physics written by Georg G. Raffelt and published by University of Chicago Press. This book was released on 1996-05 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of what we know about neutrinos is revealed by astronomical observations, and the same applies to the axion, a conjectured new particle that is a favored candidate for the main component of the dark matter of the universe.
Download or read book Particle Physics written by Necia Grant Cooper and published by CUP Archive. This book was released on 1988-04-29 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains the emergence of a profoundly new understanding of the fundamental forces of Nature.
