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Hadronic loops and the OZI rule

Description: Arguments based on unitarity indicate that hadronic loop diagrams should produce large violations of the OZI (Okubo-Zweig-Iizuka) rule. The mechanism by which these corrections are evaded has long been a mystery. We have found that there is an exact cancellation of all such loops in a particular (quark model) limit and that, at least for the rho-->omega system which we have studied in detail, the cancellation is maintained in a realistic calculation which takes into account departures from this limit.
Date: August 1, 1991
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department

Performance of CDF for B physics

Description: Hadron colliders can be an abundant source of heavy flavor, but pose a challenge to isolate the physics signals from the high backgrounds. The upgraded CDFII detector, with its precise tracking capabilities and powerful trigger system, is well equipped for this task. The detector is described with an emphasis on actual performance and on techniques to maximize the heavy flavor yield. Some first heavy flavor results are summarized.
Date: June 11, 2003
Creator: Oldeman, R.
Partner: UNT Libraries Government Documents Department

Heavy flavor lifetimes and lifetime differences

Description: The authors give an overview of heavy flavour lifetime measurements, focusing on recent results from the Tevatron and the B factories. In the first part of this article we summarize the status and latest measurements of B-hadron lifetimes and lifetime ratios, including some recent result from the Tevatron and the B factories, and compare those results with the predictions from Heavy Quark Expansion (HQE). Future prospects for lifetime measurements at the B factories and the Tevatron are discussed. In the second part, we review the status and prospects of measuring the difference between the lifetimes of the two CP eigenstates in the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} system.
Date: September 17, 2003
Creator: Rademacker, Jonas
Partner: UNT Libraries Government Documents Department

Calculation of 239Pu(n,2n) Cross Section by the Subtraction and the Ratio Methods

Description: The {sup 239}Pu(n,2n) and the {sup 235}U(n,2n) cross section are estimated by applying unitarity in several approaches: a subtraction method and also by using a ratio approach that relates the above cross sections to the {sup 238}U(n,2n) cross section and the {sup 239}Pu(n,2n) cross section to the {sup 235}U(n,2n) cross section, respectively. Also, a self-consistent, simultaneous analysis of the cross section data of four nuclei, {sup 239}Pu, {sup 235}U, {sup 238}U and {sup 232}Th, was undertaken to evaluate the {sup 239}Pu(n,2n) cross section at 11 MeV.
Date: September 28, 2000
Creator: Mavratil, P. & McNabb, D.P.
Partner: UNT Libraries Government Documents Department

On the Euler angles for SU(N)

Description: In this paper we reconsider the problem of the Euler parametrization for the unitary groups. After constructing the generic group element in terms of generalized angles, we compute the invariant measure on SU(N) and then we determine the full range of the parameters, using both topological and geometrical methods. In particular, we show that the given parametrization realizes the group SU(N+1) as a fibration of U(N) over the complex projective space CP{sup n}. This justifies the interpretation of the parameters as generalized Euler angles.
Date: October 20, 2005
Creator: Cerchiai, Bianca L; Bertini, S. & Cacciatori, Sergio L.
Partner: UNT Libraries Government Documents Department

Measurement of $\phi_s$ at D{\O} Experiment

Description: Recent measurements of the D0 experiment related to the search for new phenomena beyond the Standard Model are reviewed. The new measurement of the like-sign dimuon charge asymmetry reveals a 3.2{sigma} deviation from the SM prediction, while the updated study of the B{sub s} {yields} J/{psi}{phi} decay demonstrates a better agreement with the SM. All experimental results on the CP violation in mixing are currently consistent with each other. The D0 collaboration has much more statistics to analyze, and all these results can be significantly improved in the future.
Date: January 1, 2011
Creator: Borissov, G.
Partner: UNT Libraries Government Documents Department

MATRIX N/D METHOD WITH ABSORPTION AND THE UNITARITY PROBLEM IN COUPLED-CHANNEL REGGE THEORY

Description: In a crossing-symmetric Regge theory with several coupled two-particle channels, there are many-particle absorptive effects due to crossed two-particle processes. Also, some of the partial-wave amplitudes have overlapping left-hand and right-hand cuts in the s-plane, To enforce unitarity in such a theory, one needs a coupled-channel N/D method allowing arbitrary absorption parameters and overlapping cuts. These requirements lead to a nonlinear marginally singular N/D equation, which is proposed as part of a scheme to construct a coupled-channel Regge theory with exact crossing symmetry.
Date: November 1, 1979
Creator: Warnock, Robert Lee
Partner: UNT Libraries Government Documents Department

A Search for B^{+} \to \ell^{+} \nu_{\ell} Recoiling Against B^{-} \to D^{(*)0}\ell^{-}\bar{\nu}X

Description: We present a search for the decay B{sup +} {yields} {ell}{sup +} {nu}{sub {ell}} ({ell} = {tau}, {mu}, or e) in (458.9 {+-} 5.1) x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC PEP-IIB-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B{sup -} {yields} D{sup 0} {ell}{sup -}{bar {nu}}X) is selected, and in the recoil a search for B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} signal is performed. The {tau} is identified in the following channels: {tau}{sup +} {yields} e{sup +}{nu}{sub e}{nu}{sub {tau}}, {tau}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{nu}{sub {tau}}, {tau}{sup +} {yields} {pi}{sup +}{nu}{sub {tau}}, and {tau}{sup +} {yields} {pi}{sup +}{pi}{sup 0}{nu}{sub {tau}}. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. We determine from the dataset a preliminary measurement of {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.8 {+-} 0.1) x 10{sup -4}, which excludes zero at 2.4{sigma}, and f{sub B} = 230 {+-} 57 MeV. Combination with the hadronically tagged measurement yields {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}) = (1.8 {+-} 0.6) x 10{sup -4}. We also set preliminary limits on the branching fractions at {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}) < 7.7 x 10{sup -6} (90% C.L.), {Beta}(B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}) < 11 x 10{sup -6} (90% C.L.), and {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) < 3.2 x 10{sup -4} (90% C.L.).
Date: April 17, 2009
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department

How Well Do We Know the Unitarity Triangle? An Experimental Review

Description: In the past 10 years our knowledge of the parameters {rho} and {eta} of the Cabibbo-Kobayashi-Maskawa matrix has improved substantially. This article reviews the measurements that contributed to this advance, and discusses their implication in terms of understanding CP violation in the Standard Model and beyond.
Date: September 12, 2007
Creator: Sciolla, Gabriella & /MIT
Partner: UNT Libraries Government Documents Department

Evidence for B- to rho0rho0 Decay and Implications for the CKM Angle alpha

Description: The authors search for the decays B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0}, B{sup 0} {yields} {rho}{sup 0} f{sub 0}(980), and B{sup 0} {yields} f{sub 0}(980) f{sub 0}(980) in a sample of about 384 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They find evidence for B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} with 3.5{sigma} significance and measure the branching fraction {Beta} = (1.07 {+-} 0.33 {+-} 0.19) x 10{sup -6} and longitudinal polarization fraction f{sub L} = 0.87 {+-} 0.13 {+-} 0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the CKM unitarity angle {alpha} due to penguin contributions in B {yields} {rho}{rho} decays is 18{sup o} at the 1{sigma} level. They also set upper limits on the B{sup 0} {yields} {rho}{sup 0} f{sub 0}(980) and B{sup 0} {yields} f{sub 0}(980)f{sub 0}(980) decay rates.
Date: January 3, 2007
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Hadronic B decays at BaBar and Belle

Description: The authors review recent results of the BABAR and Belle Collaborations on the {alpha} and {gamma} angles of the unitarity triangle, on the B {yields} K{pi}{pi} Dalitz-plot analyses, and on the searches for baryonic B decays and for B {yields} D{bar D} decays.
Date: August 11, 2008
Creator: Lombardo, Vincenzo & /Milan U. /INFN, Milan
Partner: UNT Libraries Government Documents Department

Measurement of the Branching Fraction, Polarization, and CP Asymmetries in B0->rho0rho0 Decay, and Implications for the CKM Angle alpha

Description: We study B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} decays in a sample of 465 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider located at the Stanford Linear Accelerator Center (SLAC). We measure the branching fraction {Beta} = (0.92 {+-} 0.32 {+-} 0.14) x 10{sup -6} and longitudinal polarization fraction f{sub L} = 0.75{sub -0.14}{sup +0.11} {+-} 0.04, where the first uncertainty is statistical and the second is systematic. The evidence for the B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} signal has a significance of 3.1 standard deviations, including systematic uncertainties. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S{sub L}{sup 00} = (0.3 {+-} 0.7 {+-} 0.2) and C{sub L}{sup 00} = (0.2 {+-} 0.8 {+-} 0.3). They study the implication of these results for the unitarity triangle angle {alpha}.
Date: September 10, 2008
Creator: Aubert, B
Partner: UNT Libraries Government Documents Department

Measurements of the CKM Angle Alpha at BaBar

Description: The authors present improved measurements of the branching fractions and CP-asymmetries fin the B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and B{sup +} {yields} {rho}{sup +}{rho}{sup 0} decays, which impact the determination of {alpha}. The combined branching fractions of B {yields} K{sub 1}(1270){pi} and B {yields} K{sub 1}(1400){pi} decays are measured for the first time and allow a novel determination of {alpha} in the B{sup 0} {yields} {alpha}{sub 1}(1260){sup {+-}}{pi}{sup {-+}} decay channel. These measurements are performed using the final dataset collected by the BaBar detector at the PEP-II B-factory. The primary goal of the experiments based at the B factories is to test the Cabibbo-Kobayashi-Maskawa (CKM) picture of CP violation in the standard model of electroweak interactions. This can be achieved by measuring the angles and sides of the Unitarity Triangle in a redundant way.
Date: April 4, 2012
Creator: Stracka, Simone & /Milan U. /INFN, Milan
Partner: UNT Libraries Government Documents Department

B^0 to \pi^+ \pi^- \pi^0Time Dependent Dalitz Analysis at BaBar

Description: The author presents here results of a time-dependent analysis of the Dalitz structure of neutral B meson decays to {pi}{sup +}{pi}{sup -}{pi}{sup 0} from a dataset of 346 million B{bar B} pairs collected at the {Upsilon}(4S) center of mass energy by the BaBar detector at the SLAC PEP-II e{sup +}e{sup -} accelerator. No significant CP violation effects are observed and 68% confidence interval is derived on the weak angle {alpha} to be [75,152].
Date: April 6, 2007
Creator: Cavoto, Gianluca
Partner: UNT Libraries Government Documents Department

Simplified Unitarity Triangles for the Lepton Sector

Description: Encouraged by the latest SNO results, we consider the lepton mixing matrix in the approximation that the {nu}{sub 2} mass eigenstate is trimaximally (democratically) mixed. This suggests a new parameterization of the remaining mixing degrees of freedom, which eschews mixing angles, dealing instead, directly with the complex parameter U{sub e3} of the mixing matrix. Unitarity triangles then take a particularly simple form, which we hope will facilitate comparison with experiment.
Date: January 18, 2006
Creator: Bjorken, James D.; /SLAC; Harrison, P.F.; U., /Warwick; Scott, W.G. & /Rutherford
Partner: UNT Libraries Government Documents Department

Measurement of alpha / phi_2 from B to pi pi Decays

Description: The current results on B {yields} {pi}{pi} decays and SU(2) constraints on the Unitarity Triangle angle {alpha} or {phi}{sub 2} from the B-factories are summarized. Based on these measurements, predictions of the isospin analysis constraints at the end of the lifetime of both B-factories are given.
Date: January 17, 2007
Creator: Bevan, A.J.
Partner: UNT Libraries Government Documents Department

Search for the decay K+ to pi+ gamma gamma in the pi+ momentum region P > 213 MeV/c

Description: We have searched for the K{sup +} {yields} {pi}{sup +}{gamma}{gamma} decay in the kinematic region with {pi}{sup +} momentum close to the end point. No events were observed, and the 90% confidence-level upper limit on the partial branching ratio was obtained, B(K{sup +} {yields} {pi}{sup +}{gamma}{gamma}, P > 213 MeV/c) < 8.3 x 10{sup -9} under the assumption of chiral perturbation theory including next-to-leading order ''unitarity'' corrections. The same data were used to determine an upper limit on the K{sup +} {yields} {pi}{sup +}{gamma} branching ratio of 2.3 x 10{sup -9} at the 90% confidence level.
Date: May 1, 2005
Creator: Artamonov, A.V.; Bassalleck, B.; Bhuyan, B.; Blackmore, E.W.; Bryman, D.A.; Chen, S. et al.
Partner: UNT Libraries Government Documents Department

Alpha and Beta at the B Factories

Description: We review recent experimental results on time-dependent CP asymmetries in the B system from the BABAR and Belle experiments. Measurements of the {alpha} and {beta} angles of the Unitarity Triangle of the CKM matrix are discussed. These measurements constitute stringent tests of the Standard Model, and are also used to search for new physics.
Date: October 15, 2007
Creator: Finocchiaro, Giuseppe
Partner: UNT Libraries Government Documents Department

Measurements of CP-Violating Asymmetries in B0 to a1+-(1260) pi-+ Decays

Description: The authors present measurements of CP-violating asymmetries in the decays B{sup 0} {yields} a{sub 1}{sup {+-}}(1260){pi}{sup {-+}} with a{sub 1}{sup {+-}}(1260) {yields} {pi}{sup {-+}}{pi}{sup {+-}}{pi}{sup {+-}}. The data sample corresponds to 384 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric B-factory at SLAC. They measure the time- and flavor-integrated charge asymmetry A{sub CP}{sup 1{sub 1}{+-}} = -0.07 {+-} 0.07 {+-} 0.02, the mixing-induced CP violation parameter S{sub a{sub 1}{pi}} = 0.37 {+-} 0.21 {+-} 0.07, the direct CP violation parameter C{sub a{sub 1}{pi}} = -0.10 {+-} 0.15 {+-} 0.09, and the parameter {Delta}C{sub a{sub 1}{pi}} = 0.26 {+-} 0.15 {+-} 0.07 and {Delta}S{sub a{sub 1}{pi}} = -0.14 {+-} 0.21 {+-} 0.06. From these measured quantities they extract the angle {alpha}{sub eff} = 78.6{sup o} {+-} 7.3{sup o}.
Date: March 6, 2007
Creator: Palombo, F.
Partner: UNT Libraries Government Documents Department

Measurement of sin(2beta) in Tree-dominated B^0-Decays and Ambiguity Removal

Description: The most recent results from the B-factories on the time-dependent CP asymmetries measured in B{sup 0}-decays mediated by b {yields} c{bar c}s quark-transitions are reviewed. The Standard Model interpretation of the results in terms of the parameter sin 2{beta} leads to a four-fold ambiguity on the unitarity triangle {beta} which can be reduced to a two-fold ambiguity by measuring the sign of the parameter cos 2{beta}. The results on cos 2{beta} obtained so far are reviewed.
Date: March 5, 2007
Creator: Lacker, Heiko
Partner: UNT Libraries Government Documents Department

Recent Measurements of sin2beta at BaBar

Description: The angle {beta} is the most accurately measured quantity that determines the Unitarity Triangle. In this article I review the various measurements of this angle performed by the BaBar Collaboration, and discuss their implications in the search for new physics.
Date: December 14, 2005
Creator: Sciolla, Gabriella & /MIT
Partner: UNT Libraries Government Documents Department

Strongly coupled fermions in nature and the laboratory

Description: We report on recent work on the equation of state and pairing gap of neutron matter and cold atomic systems. Results of quantum Monte Carlo calculations show that the equations of state are very similar. The neutron matter pairing gap at low densities is found to be very large but, except at the smallest densities, significantly suppressed relative to cold atoms. We also discuss recent attempts to measure and extract the pairing gap in the fully paired superfluid state at unitarity.
Date: January 1, 2008
Creator: Carlson, Joseph; Gezerlis, Alexandros & Reddy, Sanjay
Partner: UNT Libraries Government Documents Department

Heavy-light fermion mixtures at unitarity

Description: We investigate fermion pairing in the unitary regime for a mass ratio corresponding to a {sup 6}Li-{sup 40}K mixture using quantum Monte Carlo methods. The ground-state energy and the average light- and heavy-particle excitation spectrum for the unpolarized superfluid state are nearly independent of the mass ratio. In the majority light system, the polarized superfluid is close to the energy of a phase separated mixture of nearly fully polarized normal and unpolarized superfluid. For a majority of heavy particles, we find an energy minimum for a normal state with a ratio of {approx}3:1 heavy to light particles. A slight increase in attraction to k{sub F}a{approx}2.5 yields a ground state energy of nearly zero for this ratio. A cold unpolarized system in a harmonic trap at unitarity should phase separate into three regions, with a shell of unpolarized superfluid in the middle.
Date: January 1, 2009
Creator: Gezerlis, Alexandros; Carlson, Joseph; Gandol, S & Schmidt, E
Partner: UNT Libraries Government Documents Department