Engineering topics

Eigen, G

Publications and source records attributed to Eigen, G.

At least 37 records · Page 2

DOE OSTI2012

Branching Fraction Measurement of B to omega l nu decays

We present a measurement of the B{sup +} {yields} {omega}{ell}{sup +}{nu} branching fraction based on a sample of 467 million B{bar B} pairs recorded by the BABAR detector at the SLAC PEP-II e{sup +}e{sup -} collider. We observe 1041 {+-} 133 signal decays, corresponding to a branching fraction of {Beta}(B{sup +} {yields} {omega}{ell}{sup +}{nu}) = (1.15 {+-} 0.15 {+-} 0.12) x 10{sup -4}, where the first error is statistical and the second is systematic. The dependence of the decay rate on q{sup 2}, the momentum transfer squared to the lepton system, is compared to QCD predictions of the form factors based on a quark model and light-cone sum rules.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2012

A Measurement of the Semileptonic Branching Fraction of the B_s Meson

We report a measurement of the inclusive semileptonic branching fraction of the B{sub s} meson using data collected with the BABAR detector in the center-of-mass energy region above the {gamma}(4S) resonance. We use the inclusive yield of {phi} mesons and the {phi} yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B{sub s} mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the B{sub s} meson is determined to be {Beta}(B{sub s} {yields} {ell}{nu}X) = 9.5{sub -2.0}{sup +2.5}(stat){sub -1.9}{sup +1.1}(syst)%, where {ell} indicates the average of e and {mu}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2012

Observation and study of the baryonic B-meson decays B→D (*) pp̄(π)(π)

We present results for B-meson decay modes involving a charm meson, protons, and pions using 455×10⁶ BB¯¯¯ pairs recorded by the BaBar detector at the SLAC PEP-II asymmetric-energy e⁺e⁻ collider. The branching fractions are measured for the following ten decays: B¯¯¯⁰→D⁰pp̄, B¯¯¯⁰→D*⁰pp̄, B¯¯¯⁰→D⁺pp̄π⁻, B¯¯¯⁰→D*⁺pp̄π⁻, B⁻→D⁰pp̄π⁻, B⁻→D*⁰pp̄π⁻, B¯¯¯⁰→D⁰pp̄π⁻π⁺, B¯¯¯⁰→D*⁰pp̄π⁻π⁺, B⁻→D⁺pp̄π⁻π⁻, and B⁻→D*⁺pp̄π⁻π⁻. The four B⁻ and the two five-body B¯¯¯⁰ modes are observed for the first time. The four-body modes are enhanced compared to the three- and the five-body modes. In the three-body modes, the M(pp̄) and M(D(*)⁰p) invariant-mass distributions show enhancements near threshold values. In the four-body mode B¯¯¯⁰→D⁺pp̄π⁻, the M(pπ⁻) distribution shows a narrow structure of unknown origin near 1.5 GeV/c². The distributions for the five-body modes, in contrast to the others, are similar to the expectations from uniform phase-space predictions.

del Amo Sanchez, P.↗

DOE OSTI2012

Search for Bbar to Lambda_c+ X l- nu Decays in Events with a Fully Reconstructed B Meson

We present a search for semileptonic B decays to the charmed baryon {Lambda}{sub c}{sup +} based on 420 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. By fully reconstructing the recoiling B in a hadronic decay mode, we reduce non-B backgrounds and determine the flavor of the signal B. We statistically correct the flavor for the effect of the B{sup 0} mixing. We obtain a 90% confidence level upper limit of {Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X{ell}{sup -} {bar {nu}}{sub {ell}})/{Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X) < 3.5%.

43 PARTICLE ACCELERATORS↗

DOE OSTI2012

Search for the Z_1(4050)^+ and Z_2(4250)^+ States in bar B^0 to chi_{c1} K^- pi^+ and B^+ to chi_{c1} K^0_S pi^+

We search for the Z{sub 1}(4050){sup +} and Z{sub 2}(4250){sup +} states, reported by the Belle Collaboration, decaying to {chi}{sub c1}{pi}{sup +} in the decays {bar B}{sup 0} {yields} {chi}{sub c1}K{sup -}{pi}{sup +} and B{sup +} {yields} {chi}{sub c1}K{sub S}{sup 0}{pi}{sup +} where {chi}{sub c1} {yields} J/{psi}{gamma}. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center-of-mass energy 10.58 GeV, and correspond to an integrated luminosity of 429 fb{sup -1}. In this analysis, we model the background-subtracted, efficiency-corrected {chi}{sub c1}{pi}{sup +} mass distribution using the K{pi} mass distribution and the corresponding normalized K{pi} Legendre polynomial moments, and then test the need for the inclusion of resonant structures in the description of the {chi}{sub c1}{pi}{sup +} mass distribution. No evidence is found for the Z{sub 1}(4050){sup +} and Z{sub 2}(4250){sup +} resonances, and 90% confidence level upper limits on the branching fractions are reported for the corresponding B-meson decay modes.

43 PARTICLE ACCELERATORS↗

DOE OSTI2012

Study of Y(3S, 2S)-> eta Y(1S) and Y(3S, 2S) -> pi pi- Y(1S) Hadronic Transitions

We study the {Upsilon}(3S, 2S) {yields} {eta}{Upsilon}(1S) and {Upsilon}(3S, 2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S) transitions with 122 x 10{sup 6} {Upsilon}(3S) and 100 x 10{sup 6} {Upsilon}(2S) mesons collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider. We measure {Beta}[{Upsilon}(2S) {yields} {eta}{Upsilon}(1S)] = (2.39 {+-} 0.31(stat.) {+-} 0.14(syst.)) x 10{sup -4} and {Lambda}[{Upsilon}(2S) {yields} {eta}{Upsilon}(1S)]/{Lambda}[{Upsilon}(2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S)] = (1.35 {+-} 0.17(stat.) {+-} 0.08(syst.)) x 10{sup -3}. We find no evidence for {Upsilon}(3S) {yields} {eta}{Upsilon}(1S) and obtain {Beta}[{Upsilon}(3S) {yields} {eta}{Upsilon}(1S)] < 1.0 x 10{sup -4} and {Lambda}[{Upsilon}(3S) {yields} {eta}{Upsilon}(1S)]/{Lambda}[{Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S)] < 2.3 x 10{sup -3} as upper limits at the 90% confidence level. We also provide improved measurements of the {Upsilon}(2S)-{Upsilon}(1S) and {Upsilon}(3S)-{Upsilon}(1S) mass differences, 562.170 {+-} 0.007(stat.) {+-} 0.088(syst.)MeV/c{sup 2} and 893.813 {+-} 0.015(stat.) {+-} 0.107(syst.)MeV/c{sup 2}, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2012

Search for CP Violation in the Decay tau- \to pi- K^0_S (>= 0 pi0) nu_tau

We report a search for CP violation in the decay {tau}{sup -} {yields} {pi}{sup -}K{sub S}{sup 0}({>=} 0{pi}{sup 0}){nu}{sub {tau}} using a dataset of 437 million {tau} lepton pairs, corresponding to an integrated luminosity of 476 fb{sup -1}, collected with the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} storage rings. The CP-violating decay-rate asymmetry is determined to be (-0.45 {+-} 0.24 {+-} 0.11)%, approximately three standard deviations from the Standard Model prediction of (0.33 {+-} 0.01)%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2012

Search for Hadronic Decays of a Light Higgs Boson in the Radiative Decay

The authors search for hadronic decays of a light Higgs boson (A{sup 0}) produced in radiative decays of an {Upsilon}(2S) or {Upsilon}(3S) meson, {Upsilon} {yields} {gamma}A{sup 0}. The data have been recorded by the BABAR experiment at the {Upsilon}(3S) and {Upsilon}(2S) center of mass energies, and include (121.3 {+-} 1.2) x 10{sup 6} {Upsilon}(3S) and (98.3 {+-} 0.9) x 10{sup 6} {Upsilon}(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions {beta}({Upsilon}(nS) {yields} {gamma}A{sup 0}) {center_dot} {beta}(A{sup 0} {yields} hadrons) (n = 2 or 3) that range from 1 x 10{sup -6} for an A{sup 0} mass of 0.3 GeV/c{sup 2} to 8 x 10{sup -5} at 7 GeV/c{sup 2}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2012

Branching Fraction Measurements of the Color-Suppressed Decays B0bar to D()0 pi0, D()0 eta, D()0 omega, and D()0 eta_prime and Measurement of the Polarization in the Decay B0bar to D*0 omega

We report updated branching fraction measurements of the color-suppressed decays {bar B}{sup 0} {yields} D{sup 0}{pi}{sup 0}, D*{sup 0}{pi}{sup 0}, D{sup 0}{eta}, D*{sup 0}{eta}, D{sup 0}{omega}, D*{sup 0}{omega}, D{sup 0}{eta}', and D*{sup 0}{eta}'. We measure the branching fractions (x10{sup -4}): {Beta}({bar B}{sup 0} {yields} D{sup 0}{pi}{sup 0}) = 2.69 {+-} 0.09 {+-} 0.13, {Beta}({bar B}{sup 0} {yields} D*{sup 0}{pi}{sup 0}) = 3.05 {+-} 0.14 {+-} 0.28, {Beta}({bar B}{sup 0} {yields} D{sup 0}{eta}) = 2.53 {+-} 0.09 {+-} 0.11, {Beta}({bar B}{sup 0} {yields} D*{sup 0}{eta}) = 2.69 {+-} 0.14 {+-} 0.23, {Beta}({bar B}{sup 0} {yields} D{sup 0}{omega}) = 2.57 {+-} 0.11 {+-} 0.14, {Beta}({bar B}{sup 0} {yields} D*{sup 0}{omega}) = 4.55 {+-} 0.24 {+-} 0.39, {Beta}({bar B}{sup 0} {yields} D{sup 0}{eta}') = 1.48 {+-} 0.13 {+-} 0.07, and {Beta}({bar B}{sup 0} {yields} D*{sup 0}{eta}') = 1.49 {+-} 0.22 {+-} 0.15. We also present the first measurement of the longitudinal polarization fraction of the decay channel D*{sup 0}{omega}, f{sub L} = (66.5 {+-} 4.7 {+-} 1.5)%. In the above, the first uncertainty is statistical and the second is systematic. The results are based on a sample of (454 {+-} 5) x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance, with the BABAR detector at the PEP-II storage rings at SLAC. The measurements are the most precise determinations of these quantities from a single experiment. They are compared to theoretical predictions obtained by factorization, Soft Collinear Effective Theory (SCET) and perturbative QCD (pQCD). We find that the presence of final state interactions is favored and the measurements are in better agreement with SCET than with pQCD.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Observation of the Rare Decay B+ \to K+pi0pi0 and Measurement of the Quasi-two Body Contributions B+ \to K*(892)+pi0, B+ \to f0(980)K+ and B+ \to chic0K+

We report an analysis of charmless hadronic decays of charged B mesons to the final state K{sup +}{pi}{sup 0}{pi}{sup 0}, using a data sample of (470.9 {+-} 2.8) x 10{sup 6} B{bar B} events collected with the BABAR detector at the {Gamma}(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be {Beta}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = (16.2 {+-} 1.2 {+-} 1.5) x 10{sup -6} and A{sub CP}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = -0.06 {+-} 0.06 {+-} 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0}, B{sup +} {yields} f{sub 0}(980)K{sup +}, and B{sup +} {yields} {chi}{sub c0}K{sup +} quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0} and B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0} channels.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Study of B to pi l nu and B to rho l nu Decays and Determination of |V_ub|

We present an analysis of exclusive charmless semileptonic B-meson decays based on 377 million B{bar B} pairs recorded with the BABAR detector at the {Upsilon} (4S) resonance. We select four event samples corresponding to the decay modes B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}, B{sup +} {yields} {pi}{sup 0}{ell}{sup +}{nu}, B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}, and B{sup +} {yields} {rho}{sup 0}{ell}{sup +}{nu}, and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B {yields} {pi}{ell}{nu} samples, and similarly the two B {yields} {rho}{ell}{nu} samples, and measure the branching fractions {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.41 {+-} 0.05 {+-} 0.07) x 10{sup -4} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{ell}{sup +}{nu}) = (1.75 {+-} 0.15 {+-} 0.27) x 10{sup -4}, where the errors are statistical and systematic. We compare the measured distribution in q{sup 2}, the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the CKM matrix element |V{sub ub}|. Based on the measured partial branching fraction for B {yields} {pi}{ell}{nu} in the range q{sup 2} < 12 GeV{sup 2} and the most recent LCSR calculations we obtain |V{sub ub}| = (3.78 {+-} 0.13{sub -0.40}{sup +0.55}) x 10{sup -3}, where the errors refer to the experimental and theoretical uncertainties. From a simultaneous fit to the data over the full q{sup 2} range and the FNAL/MILC lattice QCD results, we obtain |V{sub ub}| = (2.95 {+-} 0.31) x 10{sup -3} from B {yields} {pi}{ell}{nu}, where the error is the combined experimental and theoretical uncertainty.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Study of di-pion Bottomonium Transitions and Search for the h_b(1P) State

We study inclusive di-pion decays using a sample of 108 x 10{sup 6} {Upsilon}(3S) events recorded with the BABAR detector. We search for the decay mode {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}h{sub b} (1P) and find no evidence for the bottomonium spin-singlet state h{sub b}(1P) in the invariant mass distribution recoiling against the {pi}{sup +}{pi}{sup -} system. Assuming the h{sub b}(1P) mass to be 9.900 GeV/c{sup 2}, we measure the upper limit on the branching fraction {Beta}[{Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}h{sub b}(1P)] < 1.2 x 10{sup -4}, at 90% confidence level. We also investigate the {chi}{sub bJ}(2P) {yields} {pi}{sup +}{pi}{sup -} {chi}{sub bJ}(1P), {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(2S), and {Upsilon}(2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S) di-pion transitions and present an improved measurement of the branching fraction of the {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(2S) decay and of the {Upsilon}(3S) - {Upsilon}(2S) mass difference.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Observation of the Baryonic B decay B0bar to Lambda_c^+ anti-Lambda K-

The authors report the observation of the baryonic B decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} with a significance larger than 7 standard deviations based on 471 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. They measure the branching fraction for the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} to be (3.8 {+-} 0.8{sub stat} {+-} 0.2{sub sys} {+-} 1.0 {sub {Lambda}{sub c}{sup +}}) x 10{sup -5}. The uncertainties are statistical, systematic, and due to the uncertainty in the {Lambda}{sub c}{sup +} branching fraction. They find that the {Lambda}{sub c}{sup +} K{sup -} invariant mass distribution shows an enhancement above 3.5 GeV/c{sup 2}.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011