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Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons (open access)

Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons

The authors report a measurement of resonance parameters of the orbitally excited (L = 1) narrow B{sup 0} mesons in decays to B{sup (*)+}{pi}{sup -} using 1.7 fb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B*{sub 2}{sup 0} state are measured to be m(B*{sub 2}{sup 0}) = 5740.2{sub -1.8}{sup +1.7}(stat.){sub -0.8}{sup +0.9}(syst.) MeV/c{sup 2} and {Lambda}(B*{sub 2}{sup 0}) = 22.7{sub -3.2}{sup +3.8}(stat.){sub -10.2}{sup +3.2}(syst.) MeV/c{sub 2}. The mass difference between the B*{sub 2}{sup 0} and B{sub 1}{sup 0} states is measured to be 14.9{sub -2.5}{sup +2.2}(stat.){sub -1.4}{sup +1.2}(syst.) MeV/c{sup 2}, resulting in a B{sub 1}{sup 0} mass of 5725.3{sub -2.2}{sup +1.6}(stat.){sub -1.5}{sup +1.4}(syst.) MeV/c{sup 2}. This is currently the most precise measurement of the masses of these states and the first measurement of the B*{sub 2}{sup 0} width.
Date: September 1, 2008
Creator: Aaltonen, : T.
System: The UNT Digital Library
Search for the Flavor Changing Neutral Current Decay t $\to Zq$ in $p \bar{p}$ Collisions at $\sqrt{s}=1.96$ (open access)

Search for the Flavor Changing Neutral Current Decay t $\to Zq$ in $p \bar{p}$ Collisions at $\sqrt{s}=1.96$

We report a search for the flavor changing neutral current (FCNC) decay of the top quark t {yields} Zq (q = u, c) in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 1.9 fb{sup -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+ {ge} 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 {yields} Zq) < 3.7% at 95% C.L.
Date: May 1, 2008
Creator: Aaltonen, : T.
System: The UNT Digital Library
Measurement of b-jet Shapes in Inclusive Jet Production in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of b-jet Shapes in Inclusive Jet Production in p anti-p Collisions at s**(1/2) = 1.96-TeV

We present a measurement of the shapes of b-jets using 300 pb{sup -1} of data obtained with the upgraded Collider Detector at Fermilab (CDF II) in p{bar p} collisions at center of mass energy {radical}s = 1.96 TeV. This measurement covers a wide transverse momentum range, from 52 to 300 GeV/c. Samples of heavy-flavor enhanced jets together with inclusive jets are used to extract the average shapes of b-jets. The b-jets are expected to be broader than inclusive jets. Moreover, b-jets containing a single b-quark are expected to be narrower than those containing a b{bar b} pair from gluon splitting. The measured b-jet shapes are found to be significantly broader than expected from the pythia and HERWIG Monte Carlo simulations. This effect may arise from an underestimation of the fraction of b-jets originating from gluon splitting in these simulations.
Date: June 1, 2008
Creator: Aaltonen, T.
System: The UNT Digital Library
First Measurement of ZZ Production in panti-p Collisions at s**(1/2) = 1.96-TeV (open access)

First Measurement of ZZ Production in panti-p Collisions at s**(1/2) = 1.96-TeV

We report the first measurement of the cross section for Z boson pair production at a hadron collider. This result is based on a data sample corresponding to 1.9 fb{sup -1} of integrated luminosity from p{bar p} collisions at {radical}s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. In the {ell}{ell}{ell}{prime}{ell}{prime} channel, we observe three ZZ candidates with an expected background of 0.096{sub -0.063}{sup +0.092} events. In the {ell}{ell}{nu}{nu} channel, we use a leading-order calculation of the relative ZZ and WW event probabilities to discriminate between signal and background. In the combination of {ell}{ell}{ell}{prime}{ell}{prime} and {ell}{ell}{nu}{nu} channels, we observe an excess of events with a probability of 5.1 x 10{sup -6} to be due to the expected background. This corresponds to a significance of 4.4 standard deviations. The measured cross section is {sigma}(p{bar p} {yields}ZZ) = 1.4{sub -0.6}{sup +0.7} (stat.+syst.) pb, consistent with the standard model expectation.
Date: January 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Forward-Backward Asymmetry in Top Quark Production in ppbar Collisions at sqrt{s}=1.96 TeV (open access)

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

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.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Inclusive Search for Squark and Gluino Production in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

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

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.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in p anti-p Collisions at s**(1/2) = 1.96-TeV

None
Date: January 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Search for Hadronic Decays of W and Z Bosons in Photon Events in p anti-p Collisions at s**(1/2) = 1.96-GeV (open access)

Search for Hadronic Decays of W and Z Bosons in Photon Events in p anti-p Collisions at s**(1/2) = 1.96-GeV

None
Date: March 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing (open access)

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

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.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Search for Heavy Top-like Quarks Using Lepton Plus Jets Events in 1.96-TeV p anti-p Collisions (open access)

Search for Heavy Top-like Quarks Using Lepton Plus Jets Events in 1.96-TeV p anti-p Collisions

None
Date: January 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Search for New Heavy Particles Decaying to Z0 Z0 ---> eeee in p - anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Search for New Heavy Particles Decaying to Z0 Z0 ---> eeee in p - anti-p Collisions at s**(1/2) = 1.96-TeV

We report the results of a search for the anomalous production of a massive particle decaying to four electrons via two Z{sup 0} bosons in 1.1 fb{sup -1} of p{bar p} collisions at {radical}s =1.96 TeV collected by the CDF II detector at Fermilab. We employ optimized electron identification criteria to maximize acceptance and efficiency. We estimate the backgrounds in the invariant mass range 500-1000 GeV/c{sup 2} to be 0.028 {+-} 0.009 (stat) {+-} 0.011 (syst) events. We observe zero events in this search region. Assuming a Randall-Sundrum graviton production model, we set 95% CL limits on {sigma} x BF(G {yields} Z{sup 0}Z{sup 0}) < 4-6 pb, depending on the graviton mass.
Date: January 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M.G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Global Search for New Physics with 2.0 fb88-1 at CDF (open access)

Global Search for New Physics with 2.0 fb88-1 at CDF

Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (VISTA) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for 'bumps' that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV reveals no indication of physics beyond the standard model.
Date: September 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Measurement of the fraction of t anti-t production via gluon-gluon fusion in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of the fraction of t anti-t production via gluon-gluon fusion in p anti-p collisions at s**(1/2) = 1.96-TeV

None
Date: July 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Measurement of the Single Top Quark Production Cross Section at CDF (open access)

Measurement of the Single Top Quark Production Cross Section at CDF

We report a measurement of the single top quark production cross section in 2.2 fb{sup -1} of p{bar p} collision data collected by the Collider Detector at Fermilab at {radical}s = 1.96 TeV. Candidate events are classified as signal-like by three parallel analyses which use likelihood, matrix element, and neural network discriminants. These results are combined in order to improve the sensitivity. We observe a signal consistent with the standard model prediction, but inconsistent with the background only model by 3.7 standard deviations with a median expected sensitivity of 4.9 standard deviations. We measure a cross section of 2.2{sub -0.6}{sup +0.7}(stat+sys) pb, extract the CKM matrix element value |V{sub tb}| = 0.88{sub -0.12}{sup +0.13}(stat + sys) {+-} 0.07(theory), and set the limit |V{sub tb}| > 0.66 at the 95% C.L.
Date: September 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Search for a Higgs Boson Decaying to Two W Bosons at CDF (open access)

Search for a Higgs Boson Decaying to Two W Bosons at CDF

We present a search for a Higgs boson decaying to two W bosons in p{bar p} collisions at {radical}s = 1.96 TeV center-of-mass energy. The data sample corresponds to an integrated luminosity of 3.0 fb{sup -1} collected with the CDF II detector. We find no evidence for production of a Higgs boson with mass between 110 and 200 GeV/c{sup 2}, and determine upper limits on the production cross section. For the mass of 160 GeV/c{sup 2}, where the analysis is most sensitive, the observed (expected) limit is 0.7 pb (0.9 pb) at 95% Bayesian credibility level which is 1.7 (2.2) times the standard model cross section.
Date: September 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Search for Maximal Flavor Violating Scalars in Same-Charge Lepton Pairs in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Search for Maximal Flavor Violating Scalars in Same-Charge Lepton Pairs in p anti-p Collisions at s**(1/2) = 1.96-TeV

Models of Maximal Flavor Violation (MxFV) in elementary particle physics may contain at least one new scalar SU(2) doublet field {Phi}{sub FV} = ({eta}{sup 0},{eta}{sup +}) that couples the first and third generation quarks (q{sub 1}; q{sub 3}) via a Lagrangian term L{sub FV} = {zeta}{sub 13}{Phi}{sub FV}q{sub 1}q{sub 3}. These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb{sup -1} collected by the CDF II detector in p{bar p} collisions at {radical}s = 1.96 TeV are analyzed for evidence of the MxFV signature. For a neutral scalar {eta}{sup 0} with m{sub {eta}{sup 0}} = 200 GeV/c{sup 2} and coupling {zeta}{sub 13} = 1, {approx} 11 signal events are expected over a background of 2.1 {+-} 1.8 events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling {zeta}{sub 13} for m{sub {eta}{sup 0}} = 180-300 GeV/c{sup 2}.
Date: September 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library
Measurement of Cross Sections for b Jet Production in Events with a Z Boson in p-anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of Cross Sections for b Jet Production in Events with a Z Boson in p-anti-p Collisions at s**(1/2) = 1.96-TeV

A measurement of the b jet production cross section is presented for events containing a Z boson produced in p{bar p} collisions at {radical}s = 1.96 TeV, using data corresponding to an integrated luminosity of 2 fb{sup -1} collected by the CDF II detector at the Tevatron. Z bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy E{sub T} > 20 GeV and pseudorapidity |{eta}| < 1.5 and are identified as b jets using a secondary vertex algorithm. The ratio of the integrated Z+b jet cross section to the inclusive Z production cross section is measured to be 3.32 {+-} 0.53(stat:) {+-} 0.42(syst:) x 10{sup -3}. This ratio is also measured differentially in jet E{sub T}, jet {eta}, Z-boson transverse momentum, number of jets, and number of b jets. The predictions from leading order Monte Carlo generators and next-to-leading-order QCD calculations are found to be consistent with the measurements within experimental and theoretical uncertainties.
Date: December 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D. et al.
System: The UNT Digital Library
Measurement of the k(T) Distribution of Particles in Jets Produced in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of the k(T) Distribution of Particles in Jets Produced in p anti-p Collisions at s**(1/2) = 1.96-TeV

We present a measurement of the transverse momentum with respect to the jet axis (k{sub T}) of particles in jets produced in p{bar p} collisions at {radical}s = 1.96 TeV. Results are obtained for charged particles within a cone of opening angle 0.5 radians around the jet axis in events with dijet invariant masses between 66 and 737 GeV/c{sup 2}. The experimental data are compared to theoretical predictions obtained for fragmentation partons within the framework of resummed perturbative QCD using the modified leading log and next-to-modified leading log approximations. The comparison shows that trends in data are successfully described by the theoretical predictions, indicating that the perturbative QCD stage of jet fragmentation is dominant in shaping basic jet characteristics.
Date: November 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E. et al.
System: The UNT Digital Library
Measurement of W-Boson Helicity Fractions in Top-Quark Decays Using costheta* (open access)

Measurement of W-Boson Helicity Fractions in Top-Quark Decays Using costheta*

None
Date: November 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E. et al.
System: The UNT Digital Library
The First measurement of the top quark mass at CDF II in the lepton+jets and dilepton channels simultaneously (open access)

The First measurement of the top quark mass at CDF II in the lepton+jets and dilepton channels simultaneously

The authors present a measurement of the mass of the top quark using data corresponding to an integrated luminosity of 1.9 fb{sup -1} of p{bar p} collisions collected at {radical}s = 1.96 TeV with the CDF II detector at Fermilab's Tevatron. This is the first measurement of the top quark mass using top-antitop pair candidate events in the lepton + jets and dilepton decay channels simultaneously. They reconstruct two observables in each channel and use a non-parametric kernel density estimation technique to derive two-dimensional probability density functions from simulated signal and background samples. The observables are the top quark mass and the invariant mass of two jets from the W decay in the lepton + jets channel, and the top quark mass and the scalar sum of transverse energy of the event in the diletpon channel. They perform a simultaneous fit for the top quark mass and the jet energy scale, which is constrained in situ by the hadronic W boson mass. using 332 lepton + jets candidate events and 144 diletpon candidate events, they measure the top quark mass to be m{sub top} = 171.9 {+-} 1.7 (stat. + JES) {+-} 1.1 (other sys.) GeV/c{sup 2} = 171.9 {+-} …
Date: September 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; U., /Tsukuba; Albrow, Michael G.; Alvarez Gonzalez, B. et al.
System: The UNT Digital Library
First Direct Bound on the Total Width of the Top Quark in p anti-p Collisions at s88(1/2) = 1.96-TeV (open access)

First Direct Bound on the Total Width of the Top Quark in p anti-p Collisions at s88(1/2) = 1.96-TeV

None
Date: August 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
System: The UNT Digital Library
Search for Doubly Charged Higgs Bosons with Lepton-Flavor-Violating Decays involving Tau Leptons (open access)

Search for Doubly Charged Higgs Bosons with Lepton-Flavor-Violating Decays involving Tau Leptons

None
Date: August 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
System: The UNT Digital Library
Search for High-Mass \boldmath$e^+e^-$ Resonances in \boldmath$p\bar{p}$ Collisions at \boldmath$\sqrt{s}=$1.96 TeV (open access)

Search for High-Mass \boldmath$e^+e^-$ Resonances in \boldmath$p\bar{p}$ Collisions at \boldmath$\sqrt{s}=$1.96 TeV

A search for high-mass resonances in the e{sup +}e{sup -} final state is presented based on {radical}s =1.96 TeV p{bar p} collision data from the CDF II detector at the Fermilab Tevatron from an integrated luminosity of 2.5 fb{sup -1}. The largest excess over the standard model prediction is at an e{sup +}e{sup -} invariant mass of 240 GeV/c{sup 2}. The probability of observing such an excess arising from fluctuations in the standard model anywhere in the mass range of 150-1,000 GeV/c{sup 2} is 0.6% (equivalent to 2.5 {sigma}). We set Bayesian upper limits on {sigma}(p{bar p} {yields} X) {center_dot} {Beta}(X {yields} e{sup +}e{sup -}) at the 95% credibility level, where X is a spin 1 or spin 2 particle, and we exclude the standard model coupling Z{prime} and the Randall-Sundrum graviton for {kappa}/{bar M}{sub Pl} = 0.1 with masses below 963 and 848 GeV/c{sup 2}, respectively.
Date: October 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
System: The UNT Digital Library
A search for high-mass resonances decaying to dimuons at CDF (open access)

A search for high-mass resonances decaying to dimuons at CDF

None
Date: November 1, 2008
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
System: The UNT Digital Library