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Influence of luminosity leveling on the CDF-II B-Physics program

Description: The effective bandwidth of the CDF-II level 1 trigger is approximately 25 kHz. Some of this bandwidth is used to record events that form the data sets used by the high p{sub T} physics analyses. The remaining bandwidth is used by triggers that are sensitive to hadronic B decays and provide one of the most important samples used for the study of B{sub s}{sup 0} mixing. At high luminosities, the hadronic B triggers have rates that greatly exceed the available bandwidth. Rather than incur large dead-times associated with these excessive rates, these B triggers are prescaled to limit the total trigger rate to the effective level 1 trigger bandwidth. The prescales are dynamically adjusted as the store progresses so that all of the bandwidth that is not used for the high p{sub T} physics program is used to record hadronic B triggers. In principle, the luminosity could be held at a more constant level throughout the store in such a way that the integrated luminosity would be the same as that obtained from a normal store. It has been suggested that this would allow B triggers to be recorded with lower prescales and consequently with higher B{sub s}{sup 0} signal efficiencies. This note describes a parametric model of the high p{sub T} and hadronic B triggers used by CDF and compares the yields of reconstructed B{sub s}{sup 0} decays that would result with and without luminosity leveling.
Date: May 1, 2005
Creator: Jones, Matthew; U., /Purdue; Lewis, Jonathan & /Fermilab
Partner: UNT Libraries Government Documents Department

Design, simulation, fabrication, and preliminary tests of 3D CMS pixel detectors for the super-LHC

Description: The Super-LHC upgrade puts strong demands on the radiation hardness of the innermost tracking detectors of the CMS, which cannot be fulfilled with any conventional planar detector design. The so-called 3D detector architectures, which feature columnar electrodes passing through the substrate thickness, are under investigation as a potential solution for the closest operation points to the beams, where the radiation fluence is estimated to reach 10{sup 16} n{sub eq}/cm{sup 2}. Two different 3D detector designs with CMS pixel readout electronics are being developed and evaluated for their advantages and drawbacks. The fabrication of full-3D active edge CMS pixel devices with p-type substrate has been successfully completed at SINTEF. In this paper, we study the expected post-irradiation behaviors of these devices with simulations and, after a brief description of their fabrication, we report the first leakage current measurement results as performed on wafer.
Date: January 1, 2010
Creator: Koybasi, Ozhan; U., /Purdue; Bortoletto, Daniela; U., /Purdue; Hansen, Thor-Erik; /SINTEF, Oslo et al.
Partner: UNT Libraries Government Documents Department

Revised Proposal to Search for Heavy Resonances

Description: During October 1974, we submitted a most timely proposal to search for narrow, heavy resonances by measuring the effective mass spectrum of {pi}{pi}, {pi}K, KK, {pi}p, Kp and {bar p}p pairs. The subsequent discovery of a heavy, narrow resonance at SLAC and BNL caused much excitement and raised many new questions. In part, this may have been the reason why our proposal (No. 357) did not receive the consideration we feel it strongly deserved. We therefore resubmit our proposal, with additional clarification and improvement, and hope that the Program Advisory Committee and the Director will act favorably on our request to make these measurements.
Date: December 1, 1974
Creator: Jovanovic, D.; Lundy, R.; /Fermilab; Finley, D.; Loeffler, F.; Shibata, E. et al.
Partner: UNT Libraries Government Documents Department

Very high energy proton proton interactions: exploratory survey in a bubble chamber

Description: We propose a bubble chamber study of the general features of proton-proton interactions in the 200 to 500 GeV energy range in as much detail as measuring accuracy permits, starting with charged particle multiplicities, transverse and longitudinal momentum distributions, and detailed measurement of particle systems originating from the target proton, and extending to an exploration of the possibility of doing some four-constraint or equivalent kinematic analysis of complete events. A scanning search for any new or exotic phenomena is an important part of this proposal. We request 100,000 pictures initially in a 2 meter or 14 foot hydrogen bubble chamber, with 200 GeV or greater proton beam, {delta}p/p{le} .1%, {delta}{theta} {le} 2 mrad, and both tolerances better, if possible.
Date: June 1, 1970
Creator: Loeffler, F.J.; Barnes, V.E.; Carmony, D.D.; Christian, R.S.; Gaidos, J.A.; Garfinkel, A.F. et al.
Partner: UNT Libraries Government Documents Department

Antineutrino interactions in the deuterium filled 15 foot bubble chamber

Description: It is proposed to study the interactions of antineutrinos in deuterium. The initial request is for 300,000 pictures out of a total of one million pictures using the two-horn broad band system with 10{sup 13} protons (300 GeV) per pulse. We plan to use the external muon identifier. The physics motivation includes the following: (1) Search for charmed mesons. (2) Study of elastic and inelastic hyperon production. Only in anti-neutrino interactions can we study the {Delta}S = 1 charged current in quasi two-body interactions at energies and momentum transfers higher than that available in decays. (3) Study of the quasi elastic and pion production reactions. These data will be combined with the {nu}p data of our experiment (E-31). (4) Inclusive study of charged current interactions off neutrons and protons. (5) We will study the structure of the neutral current interaction. We will check the absence of {Delta}S = 1 neutral currents. (6) We will also look for di-muon events using the EMI. (7) We are interested in the possibility of inserting a three-radiation length metal plate in the bubble chamber to serve as a gamma converter and an electron detector.
Date: April 1, 1975
Creator: Barnes, V.E.; Carmony, D.D.; Garfinkel, A.F.; Gutay, L.; U., /Purdue; Barish, S.J. et al.
Partner: UNT Libraries Government Documents Department

Measurements of elastic and quasi-elastic scatterings of pp and -pp from ~ 20 to 40 GeV/c

Description: We propose a systematic study of elastic and quasi-elastic scatterings of pp and {bar p}p in the forward region (|t{vert_bar} {approx}< 1.5 GeV{sup 2}) from {approx} 20 to 40 GeV/c by using the single-arm spectrometer of NAL Exp. 7 without any essential change. The physics interests in this energy region warrant a precise comparison between pp and {bar p}p as a function of s(t) for fixed t(s). Therefore it is essential to use the same experimental apparatus and analysis procedures in order to minimize possible systematic errors. The possible future experiments at Serpukhov will not be able to produce sufficient flux in the secondary {bar p} beams to answer the physics questions raised in this proposal.
Date: July 1, 1971
Creator: Lai, K.W.; Turkot, F.; Gordon, H.A.; Schublein, P.; /Brookhaven; Cords, D. et al.
Partner: UNT Libraries Government Documents Department

Search for the Rare Radiative Decay: $W\rightarrow\pi\gamma$ in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV

Description: We present a search for the rare radiative decay W{sup {+-}} {yields} {pi}{sup {+-}}{gamma} using data corresponding to an integrated luminosity of 4.3 fb{sup -1} of proton-antiproton collisions at a center of mass energy of 1.96 TeV collected by the CDF experiment at Fermilab. As no statistically significant signal is observed, we set a 95% confidence level upper limit on the relative branching fraction {Gamma}(W{sup {+-}} {yields} {pi}{sup {+-}}{gamma})/{Gamma}(W{sup {+-}} {yields} e{sup {+-}}{nu}) at 6.4 x 10{sup -5}, a factor of 10 improvement over the previous limit.
Date: April 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Search for $B_s \to \mu^+\mu^-$ and $B_d \to \mu^+\mu^-$ Decays with CDF II

Description: A search has been performed for B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} and B{sup 0} {yields} {mu}{sup +}{mu}{sup -} decays using 7 fb{sup -1} of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B{sup 0} candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of {Beta}(B{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 6.0 x 10{sup -9} at 95% confidence level. We observe an excess of B{sub s}{sup 0} candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} could produce such an excess or larger is 1.9%. These data are used to determine {Beta}(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) = (1.8{sub -0.9}{sup +1.1}) x 10{sup -8} and provide an upper limit of {Beta}(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 4.0 x 10{sup -8} at 95% confidence level.
Date: July 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Search for High Mass Resonances Decaying to Muon Pairs in $\sqrt{s}=1.96$ TeV $p\bar{p}$ Collisions

Description: We present a search for a new narrow, spin-1, high mass resonance decaying to {mu}{sup +}{mu}{sup -} + X, using a matrix element based likelihood and a simultaneous measurement of the resonance mass and production rate. In data with 4.6 fb{sup -1} of integrated luminosity collected by the CDF detector in p{bar p} collisions at {radical}s = 1960 GeV, the most likely signal cross section is consistent with zero at 16% confidence level. We therefore do not observe evidence for a high mass resonance, and place limits on models predicting spin-1 resonances, including M > 1071 GeV/c{sup 2} at 95% confidence level for a Z{prime} boson with the same couplings to fermions as the Z boson.
Date: January 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

Description: We present a search for a new particle T{prime} decaying to a top-quark via T{prime} {yields} t + X, where X is an invisible particle. In a data sample with 4.8 fb{sup -1} of integrated luminosity collected by the CDF II detector at Fermilab in p{bar p} collisions with {radical}s = 1.96 TeV, we search for pair production of T0 in the lepton+jets channel, p{bar p} {yields} t{bar t} + XX {yields} {ell}{nu}bqq{prime}b + XX. We interpret our results primarily in terms of a model where T{prime} are exotic fourth generation quarks and X are dark matter particles. The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of T{prime}{bar T}{prime} {yields} t{bar t} + XX. We apply these limits to the dark matter model and exclude the fourth generation exotic quarks T{prime} at 95% confidence level up to m{sub T{prime}} = 360 GeV/c{sup 2} for m{sub x} {<=} 100 GeV/c{sup 2}.
Date: March 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Search for New Dielectron Resonances and Randall-Sundrum Gravitons at the Collider Detector at Fermilab

Description: A search for the new dielectron mass resonances using data recorded by the CDF II detector and corresponding to an integrated luminosity of 5.7 fb{sup -1} is presented. No significant excess over the expected standard model prediction is observed. In this dataset, an event with the highest dielectron mass ever observed (960 GeV/c{sup 2}) was recorded. The results are interpreted in the Randall-Sundrum (RS) model. Combined with the 5.4 fb{sup -1} diphoton analysis, the RS-graviton mass limit for the coupling k/{bar M}{sub Pl} = 0.1 is 1058 GeV/c{sup 2}, making it the strongest limit to date.
Date: March 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Observation of $B^0_s \to J/\psi K^{*0}(892)$ and $B^0_s \to J/\psi K^0_S$ Decays

Description: The authors report the first observation of two Cabibbo-suppressed decay modes of the B{sub s}{sup 0} meson. Using a sample of p{bar p} collisions at {radical}s = 1.96 TeV corresponding to 5.9 fb{sup -1} of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron, they search for new B{sub s}{sup 0} decay modes in a sample of events containing J/{psi} {yields} {mu}{sup +}{mu}{sup -} decays. They reconstruct a B{sub s}{sup 0} {yields} J/{psi} K*(892){sup 0} signal with K*(892){sup 0} {yields} K{sup +}{pi}{sup -}, observing a yield of 151 {+-} 25 events with a statistical significance of 8.0{sigma}. They also reconstruct a B{sub s}{sup 0} {yields} J/{psi} K{sub S}{sup 0} signal with K{sub S}{sup 0} {yields} {pi}{sup +}{pi}{sup -}, observing a yield of 64 {+-} 14 events with a statistical significance of 7.2{sigma}. From these yields, they extract the branching ratios {Beta}(B{sub s}{sup 0} {yields} J/{psi} K*(892){sup 0}) = (8.3 {+-} 3.8) x 10{sup -5} and {Beta}(B{sub s}{sup 0} {yields} J/{psi} K{sup 0}) = (3.5 {+-} 0.8) x 10{sup -5}, where statistical, systematic, and fragmentation-fraction uncertainties are included in the combined uncertainty.
Date: February 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Measurement of the mass difference between $t$ and $\bar{t}$ quarks

Description: We present a direct measurement of the mass difference between t and {bar t} quarks using t{bar t} candidate events in the lepton+jets channel, collected with the CDF II detector at Fermilab's 1.96 TeV Tevatron p{bar p} Collider. We make an event by event estimate of the mass difference to construct templates for top quark pair signal events and background events. The resulting mass difference distribution of data is compared to templates of signals and background using a maximum likelihood fit. From a sample corresponding to an integrated luminosity of 5.6 fb{sup -1}, we measure a mass difference, {Delta}M{sub top} = M{sub t} - M{sub {bar t}} = -3.3 {+-} 1.4 (stat) {+-} 1.0 (syst) GeV/c{sup 2}, approximately two standard deviations away from the CPT hypothesis of zero mass difference. This is the most precise measurement of a mass difference between t and its {bar t} partner to date.
Date: March 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Search for a Heavy Top-Like Quark in $p\bar{p}$ Collisions at ${\surd}s = 1.96$~TeV

Description: We present the results of a search for pair production of a heavy top-like (t') quark decaying to W q final states using data corresponding to an integrated luminosity of 5.6 fb{sup -1} collected by the CDF II detector in p{anti p} collisions at {radical}{ovr s} = 1.96 TeV. We perform parallel searches for t' {yields} W b and t' {yields} W q (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t' quark mass, we set upper limits on the t'{anti t}' production cross section and exclude a standard model fourth-generation t' quark decaying to W b (W q) with mass below 358 (340) GeV/c{sup 2} at 95% CL.
Date: July 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Search for a low mass Standard Model Higgs boson in the $\tau-\tau$ decay channel in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV

Description: We report on a search for the standard model Higgs boson decaying into pairs of {tau} leptons in p{bar p} collisions produced by the Tevatron at {radical}s = 1.96 TeV. The analyzed data sample was recorded by the CDFII detector and corresponds to an integrated luminosity of 6.0 fb{sup -1}. The search is performed in the final state with one {tau} decaying leptonically and the second one identified through its semi-hadronic decay. Since no significant excess is observed, a 95% credibility level upper limit on the production cross section times branching ratio to the {tau}{tau} final state is set for hypothetical Higgs boson masses between 100 and 150 GeV/c{sup 2}. For a Higgs boson of 120 GeV/c{sup 2} the observed (expected) limit is 14.6 (15.3) the predicted value.
Date: January 1, 2012
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Observation of the $\Xi_b^0$ Baryon

Description: The observation of the bottom, strange baryon {Xi}{sup 0}{sub b} through the decay chain {Xi}{sup 0}{sub b} {yields} {Xi}{sup +}{sub c} {pi}{sup -}, where {Xi}{sup +}{sub c} {yields} {Xi}{sup -} {pi}{sup +} {pi}{sup +}, {Xi}{sup -} {yields} {Lambda} {yields} p {pi}{sup -}, is reported using data corresponding to an integrated luminosity of 4.2 ft{sup -1} from p{anti p} collisions at {radical}{ovr s} = 1.96 TeV recorded with the Collider Detector at Fermilab. A signal of 25.3{sup +5.6}{sub -5.4} candidates is observed whose probability of arising from a background fluctuation is 3.6 x 10{sup -12}, corresponding to 6.8 Gaussian standard deviations. The {Xi}{sup 0}{sub b} mass is measured to be 5787.8 {+-} 5.0(stat) {+-} 1.3(syst) MeV/c{sup 2}. In addition, the {Xi}{sup -}{sub b} is observed through the process {Xi}{sup -}{sub b} {yields} {Xi}{sup 0}{sub c} {pi}{sup -}, where {Xi}{sup 0}{sub c} {yields} {Xi}{sup -} {pi}{sup +}, {Xi}{sup -} {yields} {Lambda} {pi}{sup -}, and {Lambda} {yields} p {pi}{sup -}.
Date: July 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Partner: UNT Libraries Government Documents Department

Observation of the Omega(b)- Baryon and Measurement of the Properties of the Xi(b)- and Omega(b)- Baryons

Description: The authors report the observation of the bottom, doubly-strange baryon {Omega}{sub b}{sup -} through the decay chain {Omega}{sub b}{sup -} {yields} J/{psi}{Omega}{sup -}, where J/{psi} {yields} {mu}{sup +} {mu}{sup -}, {Omega}{sup -} {yields} {Lambda}K{sup -}, and {Lambda} {yields} p {pi}{sup -}, using 4.2 fb{sup -1} of data from p{bar p} collisions at {radical}s = 1.96 TeV, and recorded with the Collider Detector at Fermilab. A signal is observed whose probability of arising from a background fluctuation is 4.0 x 10{sup -8}, or 5.5 Gaussian standard deviations. The {Omega}{sub b}{sup -} mass is measured to be 6054.4 {+-} 6.8(stat.) {+-} 0.9(syst.) MeV/c{sup 2}. The lifetime of the {Omega}{sub b}{sup -} baryon is measured to be 1.13{sub -0.40}{sup +0.53}(stat.) {+-} 0.02(syst.) ps. In addition, for the {Xi}{sub b}{sup -} baryon they measure a mass of 5790.9 {+-} 2.6(stat.) {+-} 0.8(syst.) MeV/c{sup 2} and a lifetime of 1.56{sub -0.25}{sup +0.27}(stat.) {+-} 0.02(syst.) ps.
Date: May 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, Jahred A.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department

Observation of Single Top Quark Production and Measurement of |Vtb| with CDF

Description: We report the observation of electroweak single top quark production in 3.2 fb{sup -1} of p{bar p} collision data collected by the Collider Detector at Fermilab at {radical}s = 1.96 TeV. Candidate events in the W+jets topology with a leptonically decaying W boson are classified as signal-like by four parallel analyses based on likelihood functions, matrix elements, neural networks, and boosted decision trees. These results are combined using a super discriminant analysis based on genetically evolved neural networks in order to improve the sensitivity. This combined result is further combined with that of a search for a single top quark signal in an orthogonal sample of events with missing transverse energy plus jets and no charged lepton. We observe a signal consistent with the standard model prediction but inconsistent with the background-only model by 5.0 standard deviations, with a median expected sensitivity in excess of 5.9 standard deviations. We measure a production cross section of 2.3{sub -0.5}{sup +0.6}(stat + sys) pb, extract the CKM matrix element value |V{sub tb}| = 0.91{sub -0.11}{sup +0.11}(stat + sys) {+-} 0.07(theory), and set a lower limit |V{sub tb}| > 0.71 at the 95% confidence level, assuming m{sub t} = 175 GeV/c{sup 2}.
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