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Suppressed B decays at CDF

Rescigno, M.; collaboration, on behalf of the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/01/2011
Relevância na Pesquisa
36.9%
We present two recent results obtained by the CDF collaboration at the Tevatron collider. New Cabibbo suppresed B_s decay modes have been observed using 5.9 inverse fb of data: B_s-> J/psi Ks and B_s->J/psi K*0. We report also on masurement of the ratios of the branching ratios (BR) of the new modes to those of the B^0-meson to the same final states: BR(B_s->J/psi K*0)/BR(B^0->J/psi K*0) = 0.062 \pm 0.009 (stat.) \pm 0.025 (sys.) \pm 0.008 (frag.) and BR(B_s->J/psi Ks)/BR(B^0->J/psi Ks) = 0.041 \pm 0.007 (stat.) \pm 0.004 (sys.) \pm 0.005 (frag.). Then we discuss the first polarization measurement in a charmless B_s decay in two light vector mesons, B_s->phi phi, using 2.9 \inverse fb of data. An angular analysis of the final state particles allows CDF to determine a longitudinal polarization fraction f_L = 0.348 \pm 0.041 (stat.) \pm 0.021 (syst.), which is inconsistent with na\"{\i}ve expectations based on the V-A nature of weak currents and confirms the pattern of lower than expected longitudinal polarization fraction in b to s penguin dominated B->VV decays. Finally, an updated measurement of the ratio of B_s->phi phi BR to that of the reference B_s->J/psi phi mode is also presented: BR (B_s->phi phi)/BR(B_s->J/psi phi) = [1.78 \pm 0.14 (stat.) \pm 0.20 ( syst.)] \cdot 10 ^ {-2}.; Comment: Based on talk presented at the Xth International Conference on Heavy Quarks and Leptons (Frascati...

Updated Search for B(s) -> mu+mu- at CDF

Kuhr, Thomas; Collaboration, for the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/11/2011
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The decay Bs -> mu+mu- is very sensitive to contributions from new physics processes. Thus the Tevatron and LHC experiments are hunting for an observation of a Bs -> mu+mu- signal. In this article the updated search for Bs -> mu+mu- and B0 -> mu+mu- by the CDF experiment is presented. The CDF result was received with great interest because an excess over the background expectation is seen, although of modest statistical significance and still consistent with the prediction of a standard model signal and other experimental results.; Comment: To appear in the proceedings of the 2011 Europhysics Conference on High Energy Physics-HEP 2011, July 21-27, 2011, Grenoble, France

Combined CDF and D0 upper limits on Fermiophobic Higgs Boson Production with up to 8.2 fb-1 of ppbar data

CDF, The; Collaborations, D0; Physics, the Tevatron New; Group, Higgs Working
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/09/2011
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We combine the results of searches by the CDF and D0 collaborations for a fermiophobic Higgs boson (H_f) produced via the processes WH_f, ZH_f, and vector-boson fusion in ppbar collisions at sqrt(s)=1.96 TeV at the Fermilab Tevatron collider. The analyses seek Higgs boson decays to W^+W^- and gamma gamma. With up to 8.2 fb-1 of integrated luminosity analyzed at CDF and up to 8.2 fb-1 at D0, we obtain a 95% CL lower bound on the mass of the Higgs boson in the fermiophobic Higgs model of 119 GeV/c^2.; Comment: Submitted to the SUSY 2011 Conference, August 28 - September 2, 2011

Combined CDF and DZero Upper Limits on Standard Model Higgs-Boson Production with up to 4.2 fb-1 of Data

Phenomena, Tevatron New; group, Higgs working; collaboration, for the CDF; collaboration, DZero
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/03/2009
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We combine results from CDF and D0 on direct searches for a standard model (SM) Higgs boson (H) in ppbar collisions at the Fermilab Tevatron at sqrt{s}=1.96 TeV. Compared to the previous Higgs Tevatron combination, more data and new channels (WH to tau nu b bbar, VH to tau tau b bbar/jj tau tau,VH to jj b bbar, t tbar H to t tbar b bbar) have been added. Most previously used channels have been reanalyzed to gain sensitivity. We use the latest parton distribution functions and gg to H theoretical cross sections when comparing our limits to the SM predictions. With 2.0-3.6 fb-1 of data analyzed at CDF, and 0.9-4.2 fb-1 at D0, the 95% C.L. upper limits on Higgs boson production are a factor of 2.5 (0.86) times the SM cross section for a Higgs boson mass of m_H=115 (165) GeV/c^2. Based on simulation, the corresponding median expected upper limits are 2.4 (1.1). The mass range excluded at 95% C.L. for a SM Higgs has been extended to 160

Search for a Higgs boson in the diphoton final state using the full CDF data set from proton-antiproton collisions at \surds = 1.96 TeV

the CDF Collaboration
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/07/2012
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A search for a narrow Higgs boson resonance in the diphoton mass spectrum is presented based on data corresponding to 10 fb-1 of integrated luminosity from proton-antiproton collisions at \surds = 1.96 TeV collected by the CDF experiment. In addition to searching for a resonance in the diphoton mass spectrum, we employ a multivariate discriminant technique for the first time in this channel at CDF. No evidence of signal is observed, and upper limits are set on the cross section times branching ratio of the resonant state as a function of Higgs boson mass. The limits are interpreted in the context of the standard model with an expected (observed) limit on the cross section times branching ratio of 9.9 (17.0) times the standard model prediction at the 95% credibility level for a Higgs boson mass of 125 GeV/c2. Moreover, a Higgs boson with suppressed couplings to fermions is excluded for masses below 114 GeV/c2 at the 95% credibility level.; Comment: 10 pages, 5 figures, for submission to Physics Letters B

Rare Decays of B and D Hadrons at CDF

Harr, R. F.; collaboration, for the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/10/2008
Relevância na Pesquisa
36.9%
Decays that are highly suppressed in the standard model are excellent places to search for effects of new physics. Decays mediated by flavor-changing neutral currents are forbidden at tree level in the SM, and are often further suppressed by helicity and the Glashow-Iliopoulos-Maiani mechanism. Exclusive final states with charged lepton pairs are a particular strength of the CDF experiment due to the large bottom and charm production cross section and the ability to efficiently separate signal from background. CDF has searched for and set the world's best limits on the rare flavor-changing neutral current decays B^0_(s) rightarrow mu^+mu^-, B^0_(s) rightarrow e^+ e^-, and D^0 rightarrow mu^+mu^-, and the lepton flavor violating decay B^0_(s) rightarrow e^+/- \mu^-/+.; Comment: proceeding for ICHEP 08, 4 pages

Combined CDF and D0 Upper Limits on Standard Model Higgs Boson Production with up to 8.2 fb-1 of Data

CDF, The; Collaborations, D0; Group, the TEVNPHWG Working
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.9%
We combine results from CDF and D0's direct searches for the standard model (SM) Higgs boson (H) produced in p-pbar collisions at the Fermilab Tevatron at sqrt(s)=1.96 TeV. The results presented here include those channels which are most sensitive to Higgs bosons with mass between 130 and 200 GeV/c^2, namely searches targeted at Higgs boson decays to W+W-, although acceptance for decays into tau+tau- and gamma gamma is included. Compared to the previous Tevatron Higgs search combination, more data have been added and the analyses have been improved to gain sensitivity. We use the MSTW08 parton distribution functions and the latest gg to H theoretical cross section predictions when testing for the presence of a SM Higgs boson. With up to 7.1 fb-1 of data analyzed at CDF, and up to 8.2 fb-1 at D0, the 95% C.L. upper limits on Higgs boson production is a factor of 0.54 times the SM cross section for a Higgs boson mass of 165 GeV/c^2. We exclude at the 95% C.L. the region 158

Search for new physics in trilepton events and limits on the associated chargino-neutralino production at CDF

CDF Collaboration; Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtie
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/09/2013
Relevância na Pesquisa
36.9%
We perform a search for new physics using final states consisting of three leptons and a large imbalance in transverse momentum resulting from proton-antiproton collisions at 1.96 TeV center-of-mass energy. We use data corresponding to 5.8 fb-1 of integrated luminosity recorded by the CDF II detector at the Tevatron collider. Our main objective is to investigate possible new low-momentum (down to 5 GeV/c) multi-leptonic final states not investigated by LHC experiments. Relative to previous CDF analyses, we expand the geometric and kinematic coverage of electrons and muons and utilize tau leptons that decay hadronically. Inclusion of tau leptons is particularly important for supersymmetry (SUSY) searches. The results are consistent with standard-model predictions. By optimizing our event selection to increase sensitivity to the minimal supergravity (mSUGRA) SUSY model, we set limits on the associated production of chargino and neutralino, the SUSY partners of the electroweak gauge bosons. We exclude cross sections up to 0.1 pb and chargino masses up to 168 GeV/c^2 at 95% CL, for a suited set of mSUGRA parameters. We also exclude a region of the two-dimensional space of the masses of the neutralino and the supersymmetric partner of the tau lepton...

Heavy Flavour Physics at CDF

Giurgiu, Gavril; collaboration, for the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/08/2008
Relevância na Pesquisa
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The CDF detector at Fermilab has accumulated more that 3/fb of data which enables unprecedented studies of heavy flavor hadron properties. We present recent CDF measurements of mass and lifetime of the Bc meson as well as lifetime, mixing and CP violation properties of Bs mesons.; Comment: 8 pages, 7 figures

Combination of CDF and D0 Measurements of the Single Top Production Cross Section

Tevatron Electroweak Working Group; for the CDF Collaboration; the D0 Collaboration
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/08/2009
Relevância na Pesquisa
36.9%
We report a combination of the CDF and D0 measurements of the inclusive single top quark production cross section in the s- and t-channels in ppbar collisions at a center of mass energy of 1.96TeV. The total integrated luminosity included in CDF's analysis is 3.2 fb^-1 and D0's analysis has 2.3 fb^-1. A Bayesian analysis is used to extract the cross section from the distributions of multivariate discriminants provided by the collaborations. For a top quark mass m_t=170 GeV/c^2, we measure a cross section of 2.76 +0.58 -0.47 pb. We extract the CKM matrix element |Vtb|=0.88+-0.07 with a 95% C.L. lower limit of |Vtb|>0.77.; Comment: TEVEWWG/singletop 2009/08, CDF Note 9870, D0-NOTE-5973, 10 pages, 4 figures

Combined CDF and D0 upper limits on gg->H W+W- and constraints on the Higgs boson mass in fourth-generation fermion models with up to 8.2 fb-1 of data

The CDF Collaboration; the D0 Collaboration; Phenomena, the Tevatron New; Group, Higgs Working
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.9%
We combine results from searches by the CDF and D0 Collaborations for a standard model Higgs boson (H) in the processes gg->H->W+W- and gg->H->ZZ in p-pbar collisions at the Fermilab Tevatron Collider at sqrt(s)=1.96 TeV. With 8.2 fb-1 of integrated luminosity analyzed at CDF and 8.1 fb-1 at D0, the 95% C.L. upper limit on sigma(gg->H)xBr(H->W+W-) is 1.01 pb at m_H=120 GeV, 0.40 pb at m_H=165 GeV, and 0.47 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 124 and 286 GeV.; Comment: Submitted to the EPS 2011 Conference

Combined CDF and Dzero Upper Limits on Standard Model Higgs-Boson Production

Phenomena, Tevatron New; group, Higgs Working; Collaboration, for the CDF; Collaboration, the D0
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/12/2007
Relevância na Pesquisa
36.99%
We combine results from CDF and D0 searches for a standard model Higgs boson (H) in ppbar collisions at the Fermilab Tevatron at sqrt{s}=1.96 TeV. With 1.0-1.9 fb-1 of data collected at CDF, and 0.9-1.7 fb-1 at D0, the 95% C.L. upper limits on Higgs production are a factor of 6.2 (1.4) higher than the SM cross section for a Higgs mass of m_Higgs = 115 (160) GeV/c^2. Based on simulation, the median expected upper limit is 4.3 (1.9). These results extend significantly the individual limits of each experiment.; Comment: Updated SM Higgs combination, compared to the combination presented at the Lepton-Photon-07 Conference, using latest CDF and D0 Higgs results

Upsilon polarization measurement at CDF

Kuhr, Thomas; Collaboration, for the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/10/2010
Relevância na Pesquisa
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Measurements of production cross sections and polarizations are essential inputs for a theoretical understanding of heavy vector meson production. In this article the CDF measurement of the Y(1S) polarization in the kinematic range |y|<0.6 and 2 < pT [GeV/c] < 40 using a data sample of 2.9/fb is described. Compared to the CDF Run I measurement, with which it agrees, it extends the covered pT range, allowing for a better comparison to predictions in the perturbative regime. The observed trend towards longitudinal polarization at high transverse momentum disagrees with predictions based on non-relativistic QCD.; Comment: To appear in the proceedings of XVIII International Workshop on Deep-Inelastic Scattering and Related Subjects, April 19 -23, 2010, Florence, Italy

Top Quark Physics at the CDF Experiment

Stelzer, Bernd; Collaboration, for the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/07/2010
Relevância na Pesquisa
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Fermilab's Tevatron accelerator is recently performing at record luminosities that enables a program systematically addressing the physics of top quarks. The CDF collaboration has analyzed up to 5/fb of proton anti-proton collisions from the Tevatron at a center of mass energy of 1.96 TeV. The large datasets available allow to push top quark measurements to higher and higher precision and have lead to the recent observation of electroweak single top quark production at the Tevatron. This article reviews recent results on top quark physics from the CDF experiment.; Comment: Proceedings of the 25th Lake Louise Winter Institute, 2010

Search for a Technicolor omega_T Particle in Events with a Photon and a b-quark Jet at CDF

The CDF Collaboration; Abe, F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/10/1998
Relevância na Pesquisa
36.99%
If the Technicolor omega_T particle exists, a likely decay mode is omega_T -> gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result of an exclusion region in the M_omega_T - M_pi_T mass plane.; Comment: 14 pages, 2 figures. Available from the CDF server (PS with figs): http://www-cdf.fnal.gov/physics/pub98/cdf4674_omega_t_prl_4.ps FERMILAB-PUB-98/321-E

Combination of CDF and D0 W-Boson Mass Measurements

CDF Collaboration; Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtie
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.99%
We summarize and combine direct measurements of the mass of the $W$ boson in $\sqrt{s} = 1.96 \text{TeV}$ proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to $2.2 \mathrm{fb}^{-1}$ of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to $4.3 \mathrm{fb}^{-1}$ of integrated luminosity. The resulting Tevatron average for the mass of the $W$ boson is $\MW = 80\,387 \pm 16 \text{MeV}$. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of $\MW = 80\,385 \pm 15 \text{MeV}$.; Comment: Submitted to Phys. Rev. D

CDF Results on $B$ Decays

Collaboration, J. Skarha for the CDF
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/06/1995
Relevância na Pesquisa
36.99%
We present recent CDF results on $B$ lifetimes, $B$ meson mass measurements, ratios of branching ratios, and rare decays. In addition, we present the first measurement of time-dependent $B_d$ mixing at CDF. Several results have been updated and a few new ones included since the workshop.; Comment: 13 pages, LaTex using world_sci.sty, 18 figures in uuencoded ps file. Contribution to the proceedings of the LISHEP95 Workshop on Heavy Flavor Physics, Rio de Janeiro, Brazil, February 20-22, 1995. Also available at: http://www-cdf.fnal.gov/physics/conf95/cdf3152_rio95_b_decays.ps

2012 Update of the Combination of CDF and D0 Results for the Mass of the W Boson

Tevatron Electroweak Working Group; for the CDF Collaboration; D0 Collaboration
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
37.06%
We summarize and combine the results on the direct measurements of the mass of the W boson in data collected by the Tevatron experiments CDF and D0 at Fermilab. Earlier results from CDF Run-0 (1988--1989), D0 and CDF Run-I (1992--1995) and D0 results from 1/fb (2002--2006) of Run-II data are now combined with two new, high statistics Run-II measurements: a CDF measurement in both electron and muon channels using 2.2/fb of integrated luminosity collected between 2002 and 2007, and a D0 measurement in the electron channel using 4.3/fb collected between 2006 and 2009. As in previous combinations, the results are corrected for inconsistencies in parton distribution functions and assumptions about electroweak parameters used in the different analyses. The resulting Tevatron average for the mass of the W boson is Mw = 80387 +- 16 MeV and a new world average including data from LEP II is Mw = 80385+- 15 MeV.; Comment: 11 pages, 1 figure

SM Higgs searches at CDF

Cuenca Almenar, Cristóbal
Fonte: Collider Detector at FermiLab (CDF) Publicador: Collider Detector at FermiLab (CDF)
Tipo: Presentación Formato: 8684691 bytes; application/pdf
ENG
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Talk at the Lake Louise Winter Institute on behalf of the CDF Collaboration (Lake Louise, Alberta Canada, Feb 18-23, 2008).; Peer reviewed

Measurement of Z/γ*+b—jet production cross section in pp collisions at √s= 1:96 TeV with the CDF detector

Ortolan, Lorenzo; Martínez Pérez, Mario
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2014 ENG
Relevância na Pesquisa
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Procesos en colisionadores hadronicos, como por ejemplo la producción de jets, pueden describirse con la teoría de la Cromodinámica Quántica (QCD). Descripciones precisas de procesos de producción de jets asociadas con un vector bosón tienen hoy en día gran relevancia ya que estos representan un fondo irreducible para otros procesos del Modelo Estándar y para la búsqueda de nueva física. El estudio experimental de la producción de b jets asociada con un bosón Z es crucial por varios motivos. Por un lado, este constituye la fuente de fondo más importante para la búsqueda del bosón de Higgs ligero que decae en una pareja de quarks b bbar y que es producido junto a un bosón Z. Este canal es uno de lo más importantes en la búsqueda del Higgs en el Tevatron en particular después que los nuevos resultados experimentales excluyeran la región de alta masa. Por otro lado, estados finales constituidos por b jets y un bosón Z son también fuente de contaminación en la búsqueda de nueva física como por ejemplo de supersimetria donde está permitido un acoplamiento fuerte del Higgs supersimétrico y el quark bottom.; La medida de la sección eficaz de producción de b jets junto a un bosón Z ha sido realizada previamente en el Tevatron por los experimentos CDF and D0 y en LHC por CMS y ATLAS. En particular la medida de CDF se realizó utilizando solo 2 fb-1 de datos y por tanto resultó limitada por la incertidumbre estadística. Esta tesis doctoral presenta una nueva medida de la sección eficaz de Z/γ* +b jets utilizando todos los datos adquiridos por CDF durante el Run II. Los bosones Z/γ* son seleccionados vía su decaimiento a dos muones o dos electrones y pidiendo su masa se encuentre entre 66 y 116 GeV/c2...