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Search for New Physics with a Dijet plus Missing Transverse Energy Signature in p-pbar Collisions at sqrt(s) = 1.96 TeV

Description: We present results of a signature-based search for new physics using a dijet plus missing transverse energy (E{sub T}) data sample collected in 2 fb{sup -1} of p{bar p} collisions at {radical}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 non-standard model process. Based on this limit the mass of a potential first or second generation scalar leptoquark is constrained to be above 187 GeV/c{sup 2}.
Date: December 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

Search for new physics in lepton + photon + X events with 929 pb**(-1) of p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors present results of a search at CDF in 929 {+-} 56 pb{sup -1} of p{bar p} collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton ({ell}, either e or {mu}) and photon ({gamma}), accompanied by missing transverse energy (E{sub T}), and/or additional leptons and photons, and jets (X). They use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher p{bar p} collisions energy, and the CDF II detector. They find 163 {ell}{gamma}E{sub T} + X events, compared to an expectation of 150.6 {+-} 13.0 events. They observe 74 {ell}{ell}{gamma} + X events, compared to an expectation of 65.1 {+-} 7.7 events. They find no events similar to the Run II ee{gamma}{gamma}E{sub T} event.
Date: February 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Partner: UNT Libraries Government Documents Department

Search for new physics in lepton + photon + X events with 305 pb**-1 of p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors present results of a search for anomalous production of events containing a charged lepton ({ell}, either e or {mu}) and a photon ({gamma}), both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb{sup -1}, a p{bar p} collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 {ell}{gamma}E{sub T} events versus a standard model expectation of 37.3 {+-} 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 {+-} 0.7 events (corresponding to a 2.7{sigma} effect), is not supported by the new data. In the signature of {ell}{ell}{gamma} + X we observe 31 events versus an expectation of 23.0 {+-} 2.7 events. In this sample we find no events with an extra photon or E{sub T} and so find no events like the one ee{gamma}{gamma}E{sub T} event observed in Run I.
Date: May 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Search for a neutral Higgs boson decaying to a W boson pair in p antip collisions at s**(1/2) = 1.96-TeV

Description: The authors present the results of a search for standard model Higgs boson production with decay to WW*, identified through the leptonic final states e{sup +}e{sup -} {bar {nu}}{nu}, e{sup {+-}}{mu}{sup {-+}} {bar {nu}}{nu} and {mu}{sup +} {mu}{sup -} {bar {nu}}{nu}. This search uses 360 pb{sup -1} of data collected from p{bar p} collisions at {radical}s = 1.96 TeV by the upgraded Collider Detector at Fermilab (CDF II). They observe no signal excess and set 95% confidence level upper limits on the production cross section times branching ratio for the Higgs boson to WW* or any new scalar particle with similar decay products. These upper limits range from 5.5 to 3.2 pb for Higgs boson masses between 120 and 200 GeV/c{sup 2}.
Date: May 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Search for anomalous production of multi-lepton events in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors report a search for the anomalous production of events with multiple charged leptons in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 346 pb{sup -1} collected by the CDF II detector at the Fermilab Tevatron. The search is divided into three-lepton and four-or-more-lepton data samples. They observe six events in the three-lepton sample and zero events in the {ge}4-lepton sample. Both numbers of events are consistent with standard model background expectations. Within the framework of an R-parity violating supergravity model, the results are interpreted as mass limits on the lightest neutralino ({bar {chi}}{sub 1}{sup 0}) and chargino ({bar {chi}}{sub 1}{sup {+-}}) particles. For one particular choice of model parameters, the limits are M({bar {chi}}{sub 1}{sup 0}) > 110 GeV/c{sup 2} and M({bar {chi}}{sub 1}{sup {+-}}) > 203 GeV/c{sup 2} at 95% confidence level; the variation of these mass limits with model parameters is presented.
Date: January 1, 2007
Creator: Abulencia, A.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF

Description: The authors present results of a search for anomalous production of two photons together with an electron, muon, {tau} lepton, missing transverse energy, or jets using p{bar p} collision data from 1.1-2.0 fb{sup -1} of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs for new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy.
Date: October 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

Search for Large Extra Dimensions in the Production of Jets and Missing Transverse Energy in ppbar Collisions at s**(1/2) = 1.96 TeV

Description: The authors present the results of a search for new physics in the jets plus missing transverse energy data sample collected from 368 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV recorded by the Collider Detector at Fermilab. They compare the number of events observed in the data with a data-based estimate of the standard model backgrounds contributing to this signature. They observe no significant excess of events, and they interpret this null result in terms of lower limits on the fundamental Planck scale for a large extra dimensions scenario.
Date: April 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Search for Technicolor Particles Produced in Association with a W Boson at CDF

Description: We present a search for the technicolor particles {rho}{sub T} and {pi}{sub T} in the process p{bar p} {yields} {rho}{sub T} {yields} W{pi}{sub T} at a center of mass energy of {radical}s = 1.96 TeV. The search uses a data sample corresponding to approximately 1.9 fb{sup -1} of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is W {yields} {ell}{nu} and {pi}{sub T} {yields} b{bar b}, b{bar c} or b{bar u} depending on the {pi}{sub T} charge. We select events with a single high-p{sub T} electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple b-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the {rho}{sub T}-{pi}{sub T} mass plane. As a result, a large fraction of the region m({rho}{sub T}) = 180-250 GeV/c{sup 2} and m({pi}{sub T}) = 95-145 GeV/c{sup 2} is excluded.
Date: December 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

Search for Supersymmetry with Gauge-Mediated Breaking in Diphoton Events with Missing Transverse Energy at CDF II

Description: The authors present the results of a search for supersymmetry with gauge-mediated breaking and {tilde {chi}}{sub 1}{sup 0} {yields} {gamma}{tilde G} in the {gamma}{gamma} + missing transverse energy final state. In 2.6 {+-} 0.2 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV recorded by the CDF II detector they observe no candidate events, consistent with a standard model background expectation of 1.4 {+-} 0.4 events. They set limits on the cross section at the 95% C.L. and place the world's best limit of 149 GeV/c{sup 2} on the {tilde {chi}}{sub 1}{sup 0} mass at {tau}{sub {tilde {chi}}{sub 1}{sup 0}} << 1 ns. They also exclude regions in the {tilde {chi}}{sub 1}{sup 0} mass-lifetime plane of {tau}{sub {tilde {chi}}{sub 1}{sup 0}} {approx}< 2 ns.
Date: October 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

Cross Section Measurements of High-p(T) Dilepton Final-State Processes Using a Global Fitting Method

Description: The authors present a new method for studying high-p{sub T} dilepton events (e{sup {+-}}e{sup {-+}}, {mu}{sup {+-}}{mu}{sup {-+}}, e{sup {+-}}{mu}{sup {-+}}) and simultaneously extracting the production cross sections of p{bar p} {yields} t{bar t}, p{bar p} {yields} W{sup +}W{sup -}, and p{bar p} {yields} Z{sup 0} {yields} {tau}{sup +}{tau}{sup -} at a center-of-mass energy of {radical}s = 1.96 TeV. They perform a likelihood fit to the dilepton data in a parameter space defined by the missing transverse energy and the number of jets in the event. The results, which use 360 pb{sup -1} of data recorded with the CDF II detector at the Fermilab Tevatron Collider, are {sigma}(t{bar t}) = 8.5{sub -2.2}{sup +2.7} pb, {sigma}(W{sup +}W{sup -}) = 16.3{sub -4.4}{sup +5.2} pb, and {sigma}(Z{sup 0} {yields} {tau}{sup +}{tau}{sup -}) = 291{sub -46}{sup +50} pb.
Date: December 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the dipion mass spectrum in X(3872) ---> J/psi pi+ pi- decays

Description: The authors measure the dipion mass spectrum in X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -} decays using 360 pb{sup -1} of {bar p}p collisions at {radical}s = 1.96 TeV collected with the CDF II detector. The spectrum is fit with predictions for odd C-parity ({sup 3}S{sub 1}, {sup 1}P{sub 1}, and {sup 3}D{sub J}) charmonia decaying to J/{psi}{pi}{sup +}{pi}{sup -}, as well as event C-parity states in which the pions are from {rho}{sup 0} decay. The latter case also encompasses exotic interpretations, such as a D{sup 0}{bar D}*{sup 0} molecule. Only the {sup 3}S{sub 1} and J/{psi} {rho} hypotheses are compatible with the data. Since {sup 3}S{sub 1} is untenable on other grounds, decay via J/{psi} {rho} is favored, which implies C = +1 for the X(3872). Models for different J/{psi}-{rho} angular momenta L are considered. Flexibility in the models, especially the introduction of {rho}-{omega} interference, enable good descriptions of the data for both L = 0 and 1.
Date: December 1, 2005
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Measurement of Z gamma Production in pbar{p} Collisions at sqrt{s} = 1.96 TeV

Description: The production rate and kinematics of photons produced in association with Z bosons are studied using 2 fb{sup -1} of p{bar p} collision data collected at the Collider Detector at Fermilab. The cross section for p{bar p} {yields} {ell}{sup +}{ell}{sup -}{gamma} + X (where the leptons {ell} are either muons or electrons with dilepton mass M{sub {ell}{ell}} > 40 GeV/c{sup 2}, and where the photon has transverse energy E{sub T}{sup {gamma}} > 7 GeV and is well separated from the leptons) is 4.6 {+-} 0.2 (stat) {+-} 0.3 (syst) {+-} 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon ET distribution from Z{gamma} events where the Z has decayed to {mu}{sup +}{mu}{sup -}, e{sup +}e{sup -}, or {nu}{bar {nu}} to set limits on anomalous (non-standard-model) trilinear couplings between photons and Z bosons.
Date: April 1, 2010
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

Measurement of correlated b-bbar production in p-pbar collisions at s**(1/2) = 1960 GeV

Description: We present a measurement of the correlated b{bar b} production cross section. The data used in this analysis were taken with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider, and correspond to an integrated luminosity of 742 pb{sup -1}. We utilize muon pairs with invariant mass 5 {le} m{sub {mu}{mu}} {le} 80 GeV/c{sup 2} produced by b{bar b} double semileptonic decays. For muons with p{sub T} {ge} 3 GeV/c and |{eta}| {le} 0.7, that are produced by b and {bar b} quarks with p{sub T} {ge} 2 GeV/c and |y| {le} 1.3, we measure {sigma}{sub b{yields}{mu},{bar b}{yields}{mu}} = 1549 {+-} 133 pb. We compare this result with theoretical predictions and previous measurements. We also report the measurement of {sigma}{sub c{yields}{mu},{bar c}{yields}{mu}}, a by-product of the study of the background to b{bar b} production.
Date: November 1, 2007
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Abulencia, A.; /Illinois U., Urbana; Adelman, J.; /Chicago U., EFI et al.
Partner: UNT Libraries Government Documents Department

Direct Measurement of the W Production Charge Asymmetry in p anti-p Collisions at s**(1/2) = 1.96-TeV

Description: We present the first direct measurement of the W production charge asymmetry as a function of the W boson rapidity y{sub W} in p{bar p} collisions at {radical}s = 1.96 TeV. We use a sample of W {yields} e{nu} events in data from 1 fb{sup -1} of integrated luminosity collected using the CDF II detector. In the region |y{sub W}| < 3.0, this measurement is capable of constraining the ratio of up and down quark momentum distributions in the proton more directly than in previous measurements of the asymmetry that are a function of the charged-lepton pseudorapidity.
Date: January 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department

Forward-Backward Asymmetry in Top Quark Production in ppbar Collisions at sqrt{s}=1.96 TeV

Description: Reconstructable final state kinematics and charge assignment in the reaction p{bar p} {yields} t{bar t} allows tests of discrete strong interaction symmetries at high energy. We define frame dependent forward-backward asymmetries for the outgoing top quark in both the p{bar p} and t{bar t} rest frames, correct for experimental distortions, and derive values at the parton-level. Using 1.9 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV recorded with the CDF II detector at the Fermilab Tevatron, we measure forward-backward top quark production asymmetries in the p{bar p} and t{bar t} rest frames of A{sub FB}{sup p{bar p}} = 0.17 {+-} 0.08 and A{sub FB}{sup t{bar t}} = 0.24 {+-} 0.14.
Date: June 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department

Measurement of sigma(chi(c2)B(chi(c2) ---> J / psi gamma) / sigma(chi(c1)B(chi(c1) ---> J / psi gamma) in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors measure the ratio of cross section times branching fraction, {sigma}{sub {chi}c2}{beta}({chi}{sub c2} {yields} J/{psi}{gamma})/{sigma}{sub {chi}c1}{beta}({chi}{sub c1} {yields} J/{psi}{gamma}), in 1.1 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV. This measurement covers the kinematic range p{sub T} (J/{psi}) > 4.0 GeV/c, |{eta}(J/{psi})| < 1.0, and p{sub T}({gamma}) > 1.0 GeV/c. For events due to prompt processes, they find R{sub p} = 0.395 {+-} 0.016(stat.) {+-} 0.015(sys.). This result represents a significant improvement in precision over previous measurements of prompt {chi}{sub c1,2} hadroproduction.
Date: March 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Partner: UNT Libraries Government Documents Department

Measurement of sigma(Lambda(b)0) / sigma(anti-B 0) x B(Lambda0(b) ---> Lambda+(c) pi-) / B(anti-B0 ---> D+ pi-) in p anti-p collisions at S**(1/2) = 1.96-TeV

Description: The authors present the first observation of the baryon decay {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +} {pi}{sup -} followed by {Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +} in 106 pb{sup -1} p{bar p} collisions at {radical}s = 1.96 TeV in the CDF experiment. IN order to reduce systematic error, the measured rate for {Lambda}{sub b}{sup 0} decay is normalized to the kinematically similar meson decay {bar B}{sup 0} {yields} D{sup +}{pi}{sup -} followed by D{sup +} {yields} {pi}{sup +}K{sup -}{pi}{sup +}. They report the ratio of production cross sections ({sigma}) times the ratio of branching fractions ({Beta}) for the momentum region integrated above p{sub T} > 6 GeV/c and pseudorapidity range |{eta}| < 1.3: {sigma}(p{bar p} {yields} {Lambda}{sub b}{sup 0}X)/{sigma}(p{bar p} {yields} {bar B}{sup 0} X) x {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})/{Beta}({bar B}{sup 0} {yields} D{sup +}{pi}{sup -}) = 0.82 {+-} 0.08(stat) {+-} 0.11(syst) {+-} 0.22 ({Beta}({Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +})).
Date: January 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Inclusive Search for Squark and Gluino Production in p anti-p Collisions at s**(1/2) = 1.96-TeV

Description: We report on a search for inclusive production of squarks and gluinos in p{bar p} collisions at {radical}s = 1.96 TeV, in events with large missing transverse energy and multiple jets of hadrons in the final state. The study uses a CDF Run II data sample corresponding to 2 fb-1 of integrated luminosity. The data are in good agreement with the standard model predictions, giving no evidence for any squark or gluino component. In an R-parity conserving minimal supergravity scenario with A{sub 0} = 0, mu < 0 and tan beta = 5, 95% C.L. upper limits on the production cross sections in the range between 0.1 pb and 1 pb are obtained, depending on the squark and gluino masses considered. For gluino masses below 280 GeV/c2, arbitrarily large squark masses are excluded at the 95%C.L., while for mass degenerate gluinos and squarks, masses below 392 GeV/c2 are excluded at the 95% C.L.
Date: November 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department

Search for H ---> b anti-b produced in association with W bosons in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors present a search for the standard model Higgs boson decaying into b{bar b} and produced in association with W bosons in p{bar p} collisions at {radical}s = 1.96 TeV. This search uses 320 pb{sup -1} of the dataset 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 they 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 m{sub H} = 110 GeV/c{sup 2} to 3 pb for m{sub H} = 150 GeV/c{sup 2}.
Date: December 1, 2005
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing

Description: The authors present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via {tilde {chi}}{sub 1}{sup 0} {yields} {gamma}{tilde G} in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of 570 {+-} 34 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, they select {gamma}+jet+missing transverse energy candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. They find 2 events, consistent with the background estimate of 1.3 {+-} 0.7 events. While the search strategy does not rely on model-specific dynamics, they set cross section limits and place the world-best 95% C.L. lower limit on the {tilde {chi}}{sub 1}{sup 0} mass of 101 GeV/c{sup 2} at {tau}{sub {tilde {chi}}{sub 1}{sup 0}} = 5 ns.
Date: April 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department