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KMC unitarity and K/sup +/ yields. pi. /sup +/. nu. anti. nu

Description: Experimental constraints on the Kobayashi-MaskawaCabibbo (KMC) matrix are surveyed and shown to provide a test of the standard model at the level of its O (..cap alpha..) radioactive corrections. The three generation prediction BR (K/sup +/ ..-->.. ..pi../sup +/..nu..) approx. = (0.35 approx. 3) x 10/sup 10/ is reviewed and the potential for enhancement up to approx. = 3 x 10/sup -9/ due to the fourth generation mixing is described. 19 refs.
Date: June 1, 1986
Creator: Marciano, William J.
Partner: UNT Libraries Government Documents Department
open access

Use of R-matrix methods for light element evaluations

Description: Some general aspects of parameterizing nuclear reaction data with a unitary, multichannel theory are discussed. The special case of R-matrix theory are discussed. The special case of R-matrix theory is considered, where the explicit separation of long- and short-range forces and the natural occurrence of energy pole terms afford a number of advantages in describing data for light-element reactions. Examples are given for both neutron- and charged-particle-induced reactions which illustrate mult… more
Date: January 1, 1980
Creator: Hale, G.M.
Partner: UNT Libraries Government Documents Department
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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
Partner: UNT Libraries Government Documents Department
open access

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 th… more
Date: September 10, 2008
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department
open access

CP Violation at BaBar

Description: Several new and updated BABAR measurements of sin 2{beta} are presented, together with the latest constraints on the Unitarity Triangle angles {alpha} and {gamma}. The higher statistics now available allow more sophisticated analysis techniques, such as time-dependent Dalitz plot fitting. Combined world-average results place tight constraints on the Unitarity Triangle. There is good agreement among the measurements and with the unitarity of the CKM matrix. This represents an impressive verifica… more
Date: January 8, 2008
Creator: Hawkes, Chris & U., /Birmingham
Partner: UNT Libraries Government Documents Department
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Measurement of CP Asymmetries and Branching Fractions in B0 -> pi+ pi-, B0 -> K+ pi-, B0 -> pi0 pi0, B0 -> K0 pi0 and Isospin Analysis of B -> pi pi Decays

Description: The authors present preliminary results of improved measurements of the CP-violating asymmetries and branching fractions in the decays B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} K{sup +}{pi}{sup -}, B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and B{sup 0} {yields} K{sup 0}{pi}{sup 0}. This update includes all data taken at the {Upsilon}(4S) resonance by the BABAR experiment at the asymmetric PEP-II B-meson factory at SLAC, corresponding to 467 {+-} 5 million B{bar B} pairs. They … more
Date: August 1, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department
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Results from the B Factories

Description: These proceedings are based on lectures given at the Helmholtz International Summer School Heavy Quark Physics at the Bogoliubov Laboratory of Theoretical Physics, Dubna, Russia, during August 2008. I review the current status of CP violation in B meson decays from the B factories. These results can be used, along with measurements of the sides of the Unitarity Triangle, to test the CKM mechanism. In addition I discuss experimental studies of B decays to final states with 'spin-one' particles.
Date: January 8, 2009
Creator: Bevan, A. & /Queen Mary, U. of London
Partner: UNT Libraries Government Documents Department
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Alpha(phi2) From a Time-Dependent Analysis of B0 -> (rhopi)0 Dalitz-plot

Description: The authors present results of time-dependent Dalitz plot analyses of B{sup 0} {yields} ({rho}{pi}){sup 0} and the corresponding constraints on the angle {alpha} or {phi}{sub 2} of the CKM unitarity triangle from the B factories.
Date: October 13, 2008
Creator: Mohanty, G & U., Warwick
Partner: UNT Libraries Government Documents Department
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Unexpected Cancellations in Gravity Theories

Description: Recent computations of scattering amplitudes show that N = 8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness first appear at one loop in the guise of the ''no-triangle hypothesis''. We study one-loop amplitudes in pure Einstein gravity and point out the existence of cancellations similar to those found previously in N = 8 supergravity. These cancellations go beyon… more
Date: July 13, 2007
Creator: Bern, Z.; Carrasco, J.J.; /UCLA; Forde, D.; /SLAC, /UCLA; Ita, H. et al.
Partner: UNT Libraries Government Documents Department
open access

One-Loop Calculations with BlackHat

Description: We describe BlackHat, an automated C++ program for calculating one-loop amplitudes, and the techniques used in its construction. These include the unitarity method and on-shell recursion. The other ingredients are compact analytic formulae for tree amplitudes for four-dimensional helicity states. The program computes amplitudes numerically, using analytic formula only for the tree amplitudes, the starting point for the recursion, and the loop integrals. We make use of recently developed on-shel… more
Date: August 1, 2008
Creator: Berger, C.F.; Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Forde, D.; Ita, H. et al.
Partner: UNT Libraries Government Documents Department
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Semileptonic Decays and Sides of the Unitarity Triangle

Description: The elements of the CKM matrix enter the expressions for the decay rates and mixing amplitudes of hadrons. In some cases, the theoretical expressions are free of strong interaction effects, for example the CP asymmetry in B {yields} J/{psi} K{sub S}{sup 0}, so that measuring the CP asymmetry directly gives the value of sin 2{beta}, with the error in the result given by the experimental error in the measurement. In most cases, however, the experimentally measured quantities depend on strong inte… more
Date: May 1, 2003
Creator: Ligeti, Zoltan; Bauer, C.; Bernard, C.; Bigi, I.; Datta, M.; del Re, D. et al.
Partner: UNT Libraries Government Documents Department
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HIGH-ENERGY-PHYSICS EXPERIMENTS WITH POLARIZED TARGETS

Description: If we are to do a workmanlike job of studying the strong interactions it is imperative that we have knowledge of the spin dependence of the forces. This implies that polarization experiments are essential. Already Bareyre, Bricman, Stirling and Villet have shown that pion-proton polarization experiments should be interpreted as indicating two new resonances not previously seen by other methods. The present-day approach to determining detailed pion-proton scattering amplitudes is to use measured… more
Date: December 1, 1966
Creator: Chamberlain, Owen
Partner: UNT Libraries Government Documents Department
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Effects of the Noncommutative Standard Model in WW Scattering

Description: We examine W pair production in the Noncommutative Standard Model constructed with the Seiberg-Witten map. Consideration of partial wave unitarity in the reactions WW {yields} WW and e{sup +}e{sup -} {yields} WW shows that the latter process is more sensitive and that tree-level unitarity is violated when scattering energies are of order a TeV and the noncommutative scale is below about a TeV. We find that WW production at the LHC is not sensitive to scales above the unitarity bounds. WW produc… more
Date: December 2, 2008
Creator: Conley, John A. & Hewett, JoAnne L.
Partner: UNT Libraries Government Documents Department
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Full one-loop amplitudes from tree amplitudes

Description: We establish an efficient polynomial-complexity algorithm for one-loop calculations, based on generalized D-dimensional unitarity. It allows automated computations of both cut-constructible and rational parts of one-loop scattering amplitudes from on-shell tree amplitudes. We illustrate the method by (re)-computing all four-, five- and six-gluon scattering amplitudes in QCD at one-loop.
Date: January 1, 2008
Creator: Giele, Walter T.; Kunszt, Zoltan & Melnikov, Kirill
Partner: UNT Libraries Government Documents Department
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Measurement of the CKM Angles at BaBar And Belle

Description: The primary goal of the BaBar and Belle experiments is to overconstrain the CKM Unitarity Triangle. Measurements of the angles of this triangle, known as {beta}, {alpha}, and {gamma} (or {phi}{sub 1}, {phi}{sub 2}, and {phi}{sub 3}) give insight into the Standard Model description of CP violation in the quark sector. BaBar and Belle have recorded almost 1 ab{sup -1} combined, and have measured {beta} to high precision. Measurements of {alpha} and {gamma} are less precise at present, but both ex… more
Date: December 5, 2007
Creator: Barlow, Nick
Partner: UNT Libraries Government Documents Department
open access

Measurement of Sin(2beta) in Tree Dominated B0 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 cos2{beta} obtained so far are reviewed.
Date: November 20, 2007
Creator: Lacker, H.
Partner: UNT Libraries Government Documents Department
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Constructing QCD one-loop amplitudes

Description: In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted after examining the behavior of the cut integrand as the unconstrained parameters of a specifically chosen parameterization of the cut loop momentum approach infinity. Measurements of new physics at the forthcoming experimental progra… more
Date: February 22, 2008
Creator: Forde, Darren
Partner: UNT Libraries Government Documents Department
open access

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 … more
Date: October 20, 2005
Creator: Cerchiai, Bianca L; Bertini, S. & Cacciatori, Sergio L.
Partner: UNT Libraries Government Documents Department
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Anomalies, Unitarity and Renormalization

Description: It is indicated how renormalizability of a gauge theory with ..gamma../sub 5/ couplings to fermions can require additional dynamical constraints to those already well known in connection with the triangle anomaly. An outline of differences from previous work is given. 11 references. (JFP)
Date: January 1, 1978
Creator: Frampton, P. H.
Partner: UNT Libraries Government Documents Department
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Discrete ambiguity resolution and baryon-resonance parameter determination. [1400 to 2200 MeV, causality, unitarity]

Description: A partial-wave analysis was performed on elastic ..pi../sup +/p data between 1400 and 2200 MeV, using principles of analyticity (to select and amalgamate data), causality and unitarity together with Barrelet zeros are the resonating waves between 1500 and 1800 MeV examined in detail, and it is shown how a new resolution of the discrete ambiguity gives, for the S31 and D33 resonances, different parameters than found in an earlier resolution using less accurate information. In either case, mass d… more
Date: April 1, 1978
Creator: Chew, D.M & Urban, M.
Partner: UNT Libraries Government Documents Department
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Measurement of. pi. /sup -/p. -->. pi. /sup 0/. pi. /sup 0/n at 6, 8 and 12 GeV/c*. [Angular distributions, S-wave enhancement]

Description: All ..gamma..'s and the neutron of this reaction are detected. From the experimental angular distributions the magnitude of the ..pi../sup 0/..pi../sup 0/ S-wave is determined for the ..pi pi.. mass range 600 to 1400 MeV and the cosinus of its phase angle (relatively to the known D-wave) is given for the range 1000 to 1400 MeV. The I = O amplitude S/sub 0/ is near the unitarity limit in the range 600 to 900 MeV and again around 1200 MeV. The data support the known facts of a very broad S-w… more
Date: January 1, 1978
Creator: Apel, W D; Auslander, J S & Muller, H
Partner: UNT Libraries Government Documents Department
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Unitarity restrictions on semi-classical approximations to certain functional integrals

Description: Estimates of physically relevant quantities (cross sections, multiplicities, correlations) in eikonal models of high-energy field theories lead to a class of semiclassical solutions to nonlinear Euler equations. The requirement of unitarity restricts these possible solutions to a unique function of energy and impact parameter.
Date: January 1, 1978
Creator: Fried, H. M.
Partner: UNT Libraries Government Documents Department
open access

Search for New Physics at a Super-B Factory

Description: The importance of a Super-B Factory in the search for New Physics, in particular, due to CP-od phase(s) from physics beyond the Standard Model is surveyed. The first point to emphasize is that we know now how to directly measure all three angles of the unitarity triangle very cleanly, i. e. without theoretical assumptions with irreducible theory error {le} 1%; however this requires much more luminosity than is currently available at B-factories. Direct searches via penguin-dominated hadronic mo… more
Date: January 5, 2004
Creator: Browder, T. E. & Soni, A.
Partner: UNT Libraries Government Documents Department
open access

Full CKM matrix with lattice QCD

Description: The authors show that it is now possible to fully determine the CKM matrix, for the first time, using lattice QCD. |V{sub cd}|, |V{sub cs}|, |V{sub ub}|, |V{sub cb}| and |V{sub us}| are, respectively, directly determined with the lattice results for form factors of semileptonic D {yields} {pi}lv, D {yields} Klv, B {yields} {pi}lv, B {yields} Dlv and K {yields} {pi}lv decays. The error from the quenched approximation is removed by using the MILC unquenced lattice gauge configurations, where the … more
Date: December 1, 2004
Creator: Okamoto, Masataka
Partner: UNT Libraries Government Documents Department
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