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排序方式: 共有251条查询结果,搜索用时 218 毫秒
111.
Aaltonen T Alvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel JA Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Auerbach B Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauce M Bauer G Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Bland KR Blocker C Blumenfeld B Bocci A Bodek A Bortoletto D Boudreau J Boveia A Brau B Brigliadori L Brisuda A 《Physical review letters》2012,108(8):081807
We report an indirect search for nonstandard model physics using the flavor-changing neutral current decays B→K(*)μ(+)μ(-). We reconstruct the decays and measure their angular distributions, as a function of q(2)=M(μμ)(2)c(2), where M(μμ) is the dimuon mass, in ppˉ collisions at √s=1.96 TeV using a data sample corresponding to an integrated luminosity of 6.8 fb(-1). The transverse polarization asymmetry A(T)(2) and the time-reversal-odd charge-and-parity asymmetry A(im) are measured for the first time, together with the K* longitudinal polarization fraction F(L) and the muon forward-backward asymmetry A(FB) for the decays B(0)→K(*0)μ(+)μ(-) and B(+)→K(*+)μ(+)μ(-). The B→K*μ(+)μ(-) forward-backward asymmetry in the most sensitive kinematic regime, 1≤q(2)<6 GeV(2)/c(2), is measured to be A(FB)=0.29(-0.23)(+0.20)(stat)±0.07(syst), the most precise result to date. No deviations from the standard model predictions are observed. 相似文献
112.
Acosta D Adelman J Affolder T Akimoto T Albrow MG Ambrose D Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arisawa T Arguin JF Artikov A Ashmanskas W Attal A Azfar F Azzi-Bacchetta P Bacchetta N Bachocou H Badgett W Barbaro-Galtieri A Barker GJ Barnes VE Barnett BA Baroiant S Bauer G Bedeschi F Behari S Belforte S Bellettini G Bellinger J Belloni A Ben-Haim E Benjamin D Beretvas A Berry T Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K 《Physical review letters》2006,96(20):202001
We measure the masses of b hadrons in exclusively reconstructed final states containing a J/psi --> mu-mu+ decay using 220 pb(-1) of data collected by the CDF II experiment. We find: m(B+) = 5279.10 +/- 0.41(stat.) +/- 0.36(sys.) MeV/c2, m(B0) = 5279.63 +/- 0.53(stat.) +/- 0.33(sys.) MeV/c2, m(B(s)0) = 5366.01 +/- 0.73(stat.) +/- 0.33(sys.) MeV/c2, m(lambda(b)0) = 5619.7 +/- 1.2(stat.) +/- 1.2(sys.) MeV/c2. m(B+) - m(B0) = -0.53 +/- 0.67(stat.) +/- 0.14(sys.) MeV/c2, m(B(s)0) - m(B0) = 86.38 +/- 0.90(stat.) +/- 0.06(sys.) MeV/c2, m(lambda(b)0) - m(B0) = 339.2 +/- 1.4(stat.) +/- 0.1(sys.) MeV/c2. The measurements of the B(s)0, lambda(b)0 mass, m(B(s)0) - m(B0) and m(lambda(b)0) - m(B0) mass difference are of better precision than the current world averages. 相似文献
113.
Abulencia A Acosta D Adelman J Affolder T Akimoto T Albrow MG Ambrose D Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arguin JF Arisawa T Artikov A Ashmanskas W Attal A Azfar F Azzi-Bacchetta P Azzurri P Bacchetta N Bachacou H Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Bartsch V Bauer G Bedeschi F Behari S Belforte S Bellettini G Bellinger J Belloni A Ben-Haim E Benjamin D Beretvas A Beringer J Berry T Bhatti A Binkley M Bisello D Bishai M 《Physical review letters》2006,96(17):171802
We searched for scalar bottom quarks 156 pb(-1) of pp collisions at radicalS = 1.96 recorded by the Collider Detector at Fermilab II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in -parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar bottom quark. Then, a scalar bottom quark can decay into a bottom quark and a neutralino. To search for this scenario, we investigated events with large missing transverse energy and at least three jets, two or more of which were identified as containing a secondary vertex from the hadronization of quarks. We found four candidate events, where 2.6 +/- 0.7 are expected from standard model processes, and placed 95% confidence level lower limits on gluino and scalar bottom quark masses of up to 280 and 240 GeV/c(2), respectively. 相似文献
114.
Abulencia A Acosta D Adelman J Affolder T Akimoto T Albrow MG Ambrose D Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arguin JF Arisawa T Artikov A Ashmanskas W Attal A Azfar F Azzi-Bacchetta P Azzurri P Bacchetta N Bachacou H Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Bartsch V Bauer G Bedeschi F Behari S Belforte S Bellettini G Bellinger J Belloni A Ben-Haim E Benjamin D Beretvas A Beringer J Berry T Bhatti A Binkley M Bisello D Bishai M 《Physical review letters》2006,96(8):081803
We present a search for Higgs bosons decaying into bb and produced in association with W bosons in pp collisions at square root of s = 1.96 TeV. This search uses 320 pb(-1) of the data set accumulated by the upgraded Collider Detector at Fermilab. Events are selected that have a high-transverse momentum electron or muon, missing transverse energy, and two jets, at least one of which is consistent with the hadronization of a b quark. Both the number of events and the dijet mass distribution are consistent with standard model background expectations, and we set 95% confidence level upper limits on the production cross section times branching ratio for the Higgs boson or any new particle with similar decay kinematics. These upper limits range from 10 pb for mH = 110 GeV/c2 to 3 pb for mH = 150 GeV/c2. 相似文献
115.
Aaltonen T Adelman J Alvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Attal A Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauer G Beauchemin PH Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Blair RE Blocker C Blumenfeld B Bocci A Bodek A Boisvert V Bortoletto D Boudreau J Boveia A Brau B Bridgeman A 《Physical review letters》2010,105(13):131801
We present results of a signature-based search for new physics using a dijet plus missing transverse energy (E(T)) data sample collected in 2 fb?1 of pp collisions at √s=1.96 TeV with the CDF II detector at the Fermilab Tevatron. We observe no significant event excess with respect to the standard model prediction and extract a 95% C.L. upper limit on the cross section times acceptance for a potential contribution from a nonstandard model process. The search is made by using novel, data-driven techniques for estimating backgrounds that are applicable to first searches at the LHC. 相似文献
116.
Aaltonen T Adelman J Alvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel J Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Attal A Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauer G Beauchemin PH Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Blair RE Blocker C Blumenfeld B Bocci A Bodek A Boisvert V Bortoletto D Boudreau J Boveia A Brau B 《Physical review letters》2010,105(19):191801
We present a search for supersymmetric neutrino ν production using the Tevatron pp collision data collected with the CDF II detector and corresponding to an integrated luminosity of 1 fb-1. We focus on the scenarios predicted by the R-parity violating (RPV) supersymmetric models in which sneutrinos decay to two charged leptons of different flavor. With the data consistent with the standard model expectations, we set upper limits on σ(pp→ν)×BR(ν→eμ,μτ,eτ) and use these results to constrain the RPV couplings as a function of the sneutrino mass. 相似文献
117.
118.
Aaltonen T Álvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel JA Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Auerbach B Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauce M Bauer G Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Bland KR Blumenfeld B Bocci A Bodek A Bortoletto D Boudreau J Boveia A Brigliadori L Brisuda A Bromberg C Brucken E 《Physical review letters》2011,107(10):102001
The observation of the bottom, strange baryon Ξ(b)(0) through the decay chain Ξ(b)(0)→Ξ(c)(+)π-, where ΞΞ(c)(+)→Ξ- π+ π+, Ξ-→Λπ-, and Λ→pπ-, is reported by using data corresponding to an integrated luminosity of 4.2 fb(-1) from pp collisions at square root(s)=1.96 TeV recorded with the Collider Detector at Fermilab. A signal of 25.3(-5.4)(+5.6) candidates is observed whose probability of arising from a background fluctuation is 3.6×10(-12), corresponding to 6.8 gaussian standard deviations. The Ξ(b)(0) mass is measured to be 5787.8±5.0(stat)±1.3(syst) MeV/c2. In addition, the Ξ(b)- baryon is observed through the process Ξ(b)-→Ξ(c)(0)π-, where Ξ(c)(0)→Ξ- π+, Ξ-→Λπ-, and Λ→pπ-. 相似文献
119.
Aaltonen T Álvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel JA Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Auerbach B Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauce M Bauer G Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Bland KR Blumenfeld B Bocci A Bodek A Bortoletto D Boudreau J Boveia A Brau B Brigliadori L Brisuda A Bromberg C 《Physical review letters》2011,107(10):102003
This Letter reports a measurement of the cross section of prompt isolated photon pair production in pp collisions at a total energy square root(s)=1.96 TeV using data of 5.36 fb(-1) integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. The measured cross section, differential in basic kinematic variables, is compared with three perturbative QCD predictions, a leading order parton shower calculation and two next-to-leading order calculations. The next-to-leading order calculations reproduce most aspects of the data. By including photon radiation from quarks before and after hard scattering, the parton shower prediction becomes competitive with the next-to-leading order predictions. 相似文献
120.
Aaltonen T Álvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel JA Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Auerbach B Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauce M Bauer G Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Bland KR Blumenfeld B Bocci A Bodek A Bortoletto D Boudreau J Boveia A Brau B Brigliadori L Brisuda A Bromberg C 《Physical review letters》2011,107(4):042001
We present the first model independent search for three-jet hadronic resonances within multijet events in sqrt(s) = 1.96 TeV pp collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinematic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background. No significant excess outside the top quark mass window is observed in data with an integrated luminosity of 3.2 fb(-1). We place 95% confidence level limits on the production cross section σ(pp → XX')×BR(gg → 3 jet + 3 jet) where X, X' = g, q, or q, with q, q → g + jet, as a function of gluino mass, in the range of 77 GeV/c2 to 240 GeV/c2. 相似文献