Download or read book Search for Flavor Changing Neutral Currents Decays in T QZ at Centre of mass Energy of 13 TeV in CMS written by 林俊廷 and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for the Flavor Changing Neutral Current Decay T Z Q at Sqrt s written by and published by . This book was released on 2009 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the results of a search for the flavor changing neutral current decay of the top quark, t → Zq, in decays of t{bar t} pairs produced in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. This search is performed on a data sample recorded by the Collider Detector at Fermilab (CDF), corresponding to an integrated luminosity of 1.9 fb−1. This search follows a previous CDF analysis that resulted in an upper limit for the branching fraction [Beta](t → Zq) of 10.4% at 95% C.L. using a dataset equivalent to 1.1 fb−1 of integrated luminosity. This thesis extends to 1.9 fb−1 of data, and has improved sensitivity to the small signal with the introduction of a template fit technique that includes systematic uncertainties by a linear interpolation between templates. Using a Feldman-Cousins construction, an upper limit at 95% C.L. is set on [Beta](t → Zq) of 3.7%, with the expected upper limit in absence of a signal is 5.0 ± 2.2% for a top mass of 175 GeV/c2.

Download or read book Search for the Flavor Changing Neutral Current Decay t rightarrow QZ in p overline p Collisions at sqrt s written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a blind search for the flavor changing neutral current decay of the top quark t → qZ in pp collisions at [special characters omitted] = 1.96TeV using a data sample corresponding to an integrated luminosity of 1.12 fb-1 collected by the Collider Detector at Fermilab (CDF), This decay is extremely rare in the standard model, and a signal at the Tevatron would be an indication of new physics. Dividing candidate events with a Z boson and four or more jets into a sample of those which have a heavy flavor jet identified by a secondary vertex algorithm and those which do not, we observe data yields consistent with background expectations. We set a 95% C.L. upper limit on the branching fraction B (t → qZ) of 11.3%, consistent with an expected upper limit of 7.8% ± 3.3%.

Download or read book Search for the Flavor Changing Neutral Current Decay T to Zq in p bar p Collisions at sqrt s written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a search for the flavor changing neutral current (FCNC) decay of the top quark t → Zq (q = u, c) in p{bar p} collisions at √s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 1.9 fb−1 collected by the CDF II detector. This decay is strongly suppressed in the standard model (SM) and a signal at the Tevatron would be an indication of physics beyond the SM. Using Z+ ≥ 4 jet final state candidate events, both with and without an identified bottom quark jet, we discriminate signal from background by exploring kinematic constraints present in FCNC events and obtain an upper limit of [Beta](t → Zq)

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 Flavor Changing Neutral Current Decay T u2192 Z Q at u221A s written by and published by . This book was released on 2009 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the results of a search for the flavor changing neutral current decay of the top quark, t → Zq, in decays of t$ar{t}$ pairs produced in p$ar{p}$ collisions at a center-of-mass energy of 1.96 TeV. This search is performed on a data sample recorded by the Collider Detector at Fermilab (CDF), corresponding to an integrated luminosity of 1.9 fb-1. This search follows a previous CDF analysis that resulted in an upper limit for the branching fraction ?(t → Zq) of 10.4% at 95% C.L. using a dataset equivalent to 1.1 fb-1 of integrated luminosity. This thesis extends to 1.9 fb-1 of data, and has improved sensitivity to the small signal with the introduction of a template fit technique that includes systematic uncertainties by a linear interpolation between templates. Using a Feldman-Cousins construction, an upper limit at 95% C.L. is set on ?(t → Zq) of 3.7%, with the expected upper limit in absence of a signal is 5.0 ± 2.2% for a top mass of 175 GeV/c2.

Download or read book Search for Flavor Changing Neutral Currents K written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for the flavor-changing neutral-current decays K/sub L/° .-->. .pi.°ee/sup /minus//, K/sub L/° .-->. ee/sup /minus// and K/sub L/° .-->. .mu./sup +-/e/sup /minus plus//. Limits obtained for these processes are BR(K/sub L/° .-->. .pi.°e+e/sup /minus//) 3.2 x 10/sup /minus/7/, BR(K/sub L/° .--. e+e/sup /minus//) 1.2 x 10/sup /minus/9/, BR(K/sub L/° .--. .mu./sup +-/e/sup /minus plus//)

Download or read book A Search for Flavor Changing Neutral Currents and Lepton Family Number Violation in Neutral Two body Charm Decays written by David Aaron Pripstein and published by . This book was released on 1997 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Updated Search for the Flavor Changing Neutral Current Decay D0 to mu mu written by and published by . This book was released on 2010 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for the flavor-changing neutral-current decay D° →??− in p{bar p} collisions at √s = 1.96TeV using 360 pb−1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. A displaced vertex trigger selects long-lived D° candidates in the?+?−,?+?−, and K−?+ decay modes. We use the Cabibbo-favored D° → K−?+ channel to optimize the selection criteria in an unbiased manner, and the kinematically similar D° →?+?− channel for normalization. We set an upper limit on the branching fraction?(D° →?+?−)

Download or read book Search for Flavor changing neutral current D Meson Decays written by and published by . This book was released on 2007 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We study the flavor-changing-neutral-current process c → u??− using 1.3 fb−1 of p{bar p} collisions at √s = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We see clear indications of the D+{sub s} and D+ →??+ →?+?−?+ final states with significance greater than four standard deviations above background for the D+ state. We search for the continuum decay of D+ →?+?+?− in the dimuon invariant mass spectrum away from the? resonance. We see no evidence of signal above background and set a limit of B(D+ →?+?+?−)

Download or read book Heavy Flavor Decays of the Z0 and a Search for Flavor Changing Neutral Currents written by and published by . This book was released on 2004 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented here are the results of a direct search for flavor changing neutral currents via the rare process Z° → bs and a measurement of R{sub bs} = [Lambda](Z° → bs)/[Lambda](Z° → hadrons). Because the decays Z° → b{bar b} and Z° → c{bar c} contribute significant backgrounds to Z° → bs, simultaneous measurements of R{sub b} = [Lambda](Z° → b{bar b})/[Lambda](Z° → hadrons) and R{sub c} = [Lambda](Z° → c{bar c})/[Lambda](Z° → hadrons) were also made. The standard double tag technique was extended and self calibrating tags were used for s, c, and b quarks. These measurements were made possible by the unique capabilities of the SLAC Large Detector (SLD) at the Stanford Linear Accelerator Center (SLAC): The b and c tags relied upon the SLD's VXD3 307 megapixel CCD vertex detector for topological and kinematic reconstruction of the B and D decay vertices; the s tag identified K{sup {+-}} mesons using the particle identification capabilities of SLD's Cherenkov Ring Imaging Detector (CRID), and K{sub S}° mesons and [Lambda] hadrons by kinematic reconstruction of their decay vertices in SLD's 5120 channel central drift chamber (CDC) particle tracking system.

Download or read book Search for Flavor Changing Neutral Current Decays of Charm Mesons written by Nicholas James Witchey and published by . This book was released on 1996 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flavor Changing Neutral Currents in Ttbar Decays at D O written by and published by . This book was released on 2011 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for flavor changing neutral currents (FCNC) in decays of top quarks. The analysis is based on a search for t{bar t} → l'[nu]l{bar l} + jets (l,{ell}' = e, [mu]) final states using 4.1 fb−1 of integrated luminosity of p{bar p} collisions at √ s = 1.96 TeV. We extract limits on the branching ratio B(t → Zq) (q = u, c quarks), assuming anomalous tuZ or tcZ couplings. We do not observe any sign of such anomalous coupling and set a limit of B

Download or read book A Search for Flavor Changing Neutral Currents and Lepton Family Number Violation in Neutral Two body Charm Decays written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents a search for three rare/forbidden neutral charm decays, D[sup 0][yields][mu]e, D[sup 0][yields][mu][mu], and D[sup 0][yields] ee. This study was based on data collected in Experiment E789 at the Fermi National Accelerator Laboratory using 800 GeV/c proton-gold interactions. Two statistical analyses are presented, one with background subtraction and the other without background subtraction. No evidence is found for any of the decays and the following upper limits are presented at the 90% confidence level.

Download or read book A Search for Effective Flavour Changing Neutral Currents in K sub L Decays written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A dedicated search for the decays K/sub L/° → [mu]e, K/sub L/° → ee and K/sub L/° → [mu][mu], was carried out at the Brookhaven National Laboratory AGS (E780). The data obtained were also used in a search for the three-body decays K/sub L/° → [pi]°l /sup /plus/1/sup -/. The two body modes were normalized to the kinelatically similar, CP violating, decay K/sub L/° → [pi]/sup (plus//[pi]/sup -/; whereas the three body modes were normalized to the decay K/sub L/° /yields/ [pi]°/pi//sup /plus//pi//sup /minus//. The search was performed on a sample of K° mesons produced in the forward direction by the interactions of 29 GeV protons on a copper target, and decaying in a 3 meter long region, starting augmented by a hydrogen Cerenkov counter and a lead glass electromagnetic calorimeter, for electron identification, and by a range stack, for muon identification. 9 refs., 5 figs., 2 tabs.

Download or read book Search for the Flavor Changing Neutral Current Decay D 1hn0 m63 1hn m63 571 mu mu with the HERA B Detector written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Top Decays Charm and Higgs Through Flavor Changing Neutral Current Process in CMS written by 邱奕寰 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: