Search NASA⌕ Search

Engineering topics

Eigen, G

Publications and source records attributed to Eigen, G.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Search for B+ meson decay to a1+ K*0

We present a search for the decay B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892). The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represent 465 million B{anti B} pairs produced in e{sup +}e{sup -} annihilation at the energy of the {Upsilon}(4S). We find no significant signal and set an upper limit at 90% confidence level on the product of branching fractions B(B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892)) x B({alpha}{sup +}{sub 1}(1260) --> {pi}{sup +}{pi}{sup -}{pi}{sup +}) of 1.8 x 10{sup -6}.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Search for b-->u transitions in B- --> DK- and B- --> D*K- Decays

We report results from an updated study of the suppressed decays B{sup -} --> DK{sup -} and B{sup -} --> D*K{sup -} followed by D --> K{sup +}{pi}{sup -}, where D{sup (*)} indicates a D{sup (*)0} or a {anti D}{sup (*)0} meson, and D{sup *} --> D{tau}{sup 0} or D{sup *} --> D{gamma}. These decays are sensitive to the CKM unitarity triangle angle {gamma} due to interference between the b --> c transition B{sup -} --> D{sup (*)0}K{sup -} followed by the double Cabibbo-suppressed decay D{sup 0} --> K{sup +}{pi}{sup -}, and the b --> u transition B{sup -} --> {anti D}{sup (*)0}K{sup -} followed by the Cabibbo-favored decay {anti D}{sup 0} --> K{sup +}{pi}{sup -}. We also report an analysis of the decay B{sup -} --> D{sup (*)}{pi}{sup -} with the D decaying into the doubly Cabibbo-suppressed mode D --> K{sup +}{pi}{sup -}. Our results are based on 467 million {Upsilon}(4S) --> B{anti B} decays collected with the BABAR detector at SLAC. We measure the ratios R{sup (*)} of the suppressed ([K{sup +}{pi}{sup -}]{sub D}K{sup -}/{pi}{sup -}) to favored ([K{sup -}{pi}{sup +}]{sub D}K{sup -}/{pi}{sup -}) branching fractions as well as the CP asymmetries A{sup (*)} of those modes. We see indications of signals for the B{sup -} --> DK{sup -} and B{sup -} --> D{sup *}{sub D{pi}{sup 0}}K{sup -} suppressed modes, with statistical significances of 2.1 and 2.2{sigma}, respectively, and we measure: R{sub DK} = (1.1 {+-} 0.6 {+-} 0.2) x 10{sup -2}, A{sub DK} = -0.86 {+-} 0.47 {sup +0.12}{sub -0.16}, R{sup *}{sub (D{pi}{sup 0})K} = (1.8 {+-} 0.9 {+-} 0.4) x 10{sup -2}, A{sup *}{sub (D{pi}{sup 0})K} = +0.77 {+-} 0.35 {+-} 0.12, R{sup *}{sub (D{gamma})K} = (1.3 {+-} 1.4 {+-} 0.8) x 10{sup -2}, A{sup *}{sub (D{gamma})K} = +0.36 {+-} 0.94 {sup +0.25}{sub -0.41}, where the first uncertainty is statistical and the second is systematic. we use a frequentist approach to obtain the magnitude of the ratio r{sub B} {equivalent_to} {vert_bar}A(B{sup -} --> {anti D}{sup 0}K{sup -})/A(B{sup -} --> D{sup 0}K{sup -}){vert_bar} = (9.5{sup +5.1}{sub -4.1})%, with r{sub B} < 16.7% at 90% confidence level. In the case of B{sup -} --> D{sup *}K{sup -} we find r{sup *}{sub B} {equivalent_to} {vert_bar}A(B{sup -} --> {anti D}{sup *0}K{sup -})/A(B{sup -} --> D{sup *0}K{sup -}){vert_bar} = (9.6{sup +3.5}{sub 5.1})%, with r{sup *}{sub B} < 15.0% at 90% confidence level.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Evidence for the decay X(3872) -> J/\psi\omega

We present a study of the decays B{sup 0,+} --> J/{psi}{pi}{sup +}{pi}{sup -}{pi}{sup 0}K{sup 0,+}, using 467x10{sup 6} B{anti B} pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872) --> J/{psi}{omega}, with product branching fractions B(B{sup +} --> X(3872)K{sup +}) x B(X(3872) --> J/{psi}{omega}) = [0.6 {+-} 0.2(stat) {+-} 0.1(syst)] x 10{sup -5}, and B(B{sup 0} --> X(3872)K{sup 0}) x B(X(3872) --> J/{psi}{omega}) = [0.6 {+-} 0.3(stat) {+-} 0.1(syst)] x 10{sup -5}. A detailed study of the {pi}{sup +}{pi}{sup -}{pi}{sup 0} mass distribution from X(3872) decay favors a negative-parity assignment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Dalitz Analysis of Ds -> K K- pi-

We perform a Dalitz plot analysis of about 100,000 D{sub s}{sup +} decays to K{sup +}K{sup -}{pi}{sup +} and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of D{sub s}{sup +} {yields} K{sup +}K{sup +}{pi}{sup -} and D{sub s}{sup +} {yields} K{sup +}K{sup +}K{sup -}. For this analysis we use a 384 fb{sup -1} data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider running at center-of-mass energies near 10.58 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurements of Charged Current Lepton Universality and |Vus| using Tau Lepton Decays to e- v v, __- v v, pi- v and K- v

Using 467 fb{sup -1} of e{sup +}e{sup -} annihilation data collected with the BABAR detector, they measure {Beta}({tau}{sup -} {yields} {mu}{sup -}{bar {nu}}{sub {mu}}{nu}{sub {tau}})/{Beta}({tau}{sup -} {yields} e{sup -} {bar {nu}}{sub e}{nu}{sub {tau}}) = (0.9796 {+-} 0.0016 {+-} 0.0036), {Beta}({tau}{sup -} {yields} {pi}{sup -} {nu}{sub {tau}})/{Beta}({tau}{sup -} {yields} e{sup -}{bar {nu}}{sub e}{nu}{sub {tau}}) = (0.5945 {+-} 0.0014 {+-} 0.0061), and {Beta}({tau}{sup -} {yields} K{sup -}{nu}{sub {tau}})/{Beta}({tau}{sup -} {yields} e{sup -}{bar {nu}}{sub e}{nu}{sub {tau}}) = (0.03882 {+-} 0.00032 {+-} 0.00057), where the uncertainties are statistical and systematic, respectively. From these precision {tau} measurements, they test the Standard Model assumption of {mu}-e and {tau}-{mu} charge current lepton universality and provide determinations of |V{sub us}| experimentally independent of the decay of a kaon.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of |Vcb| and the Form-Factor Slope in Bbar -> Dlnu Decays in Events Tagged by a Fully Reconstructed B Meson

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V{sub cb}| and the form-factor slope {rho}{sup 2} in {bar B} {yields} D{ell}{sup -} {bar {nu}}{sub {ell}} decays based on 460 million B{bar B} events recorded at the {Gamma}(4S) resonance with the BABAR detector. {bar B} {yields} D{ell}{sup -} {bar {nu}}{sub {ell}} decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure the differential decay rate and determine G(1)|V{sub cb}| = (43.0 {+-} 1.9 {+-} 1.4) x 10{sup -3} and {rho}{sup 2} = 1.20 {+-}0.09 {+-} 0.04, where G(1) is the hadronic form factor at the point of zero recoil. We also determine the exclusive branching fractions and find {Beta}(B{sup -} {yields} D{sup 0} {ell}{sup -}{bar {nu}}{sub {ell}}) = (2.31 {+-} 0.08 {+-} 0.09)% and {Beta}(B{sup 0} {yields} D{sup +} {ell}{sup -} {bar {nu}}{sub {ell}}) = (2.23 {+-} 0.11 {+-} 0.11)%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement and Interpretation of Moments in Inclusive Semileptonic Decays B-bar to X_c ell^-

We present results for the moments of observed spectra in inclusive semileptonic B-meson decays to charm hadrons {bar B} {yields} X{sub c} {ell}{sup -}{bar {nu}}. Moments of the hadronic-mass and the combined mass-and-energy spectra for different minimum electron or muon momenta between 0.8 and 1.9 GeV/c are obtained from a sample of 232 x 10{sup 6} {Gamma}(4S) {yields} B{bar B} events, collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We also present a reevaluation of the moments of electron-energy spectra and partial decay fractions B({bar B} {yields} X{sub c}e{sup -}{bar {nu}}) for minimum electron momenta between 0.6 and 1.5 GeV/c based on a sample of 51 x 10{sup 6} {Gamma}(4S) {yields} B{bar B} events. The measurements are used for the extraction of the total decay fraction, the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V{sub cb}|, the quark masses m{sub b} and m{sub c}, and four heavy-quark QCD parameters in the framework of a Heavy-Quark Expansion (HQE). We find B({bar B} {yields} X{sub c}{ell}{sup -}{bar {nu}}) = (10.64 {+-} 0.17 {+-} 0.06)% and |V{sub cb}| = (42.05 {+-} 0.45 {+-} 0.70) x 10{sup -3}.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Study of D_s J decays to D*K in inclusive e+e- interactions

We observe the decays D*{sub s1} (2710){sup +} {yields} D*K and D*{sub sJ} (2860){sup +} {yields} D*K and measure their branching fractions relative to the DK final state. We also observe, in the D*K mass spectrum, a new broad structure at a mass of (3044 {+-} 8{sub stat}(+30/-5){sub syst}) MeV/c{sup 2} having a width {Lambda} = (239 {+-} 35{sub stat}(+46/-42){sub syst}) MeV. To obtain this result we use 470 fb{sup -1} of data recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings at the Stanford Linear Accelerator Center running at center-of-mass energies near 10.6 GeV.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Searches for the baryon- and lepton-number violating decays $B^0\rightarrow\Lambda_c^ \ell^-$, $B^-\rightarrow\Lambda\ell^-$, and $B^-\rightarrow\bar{\Lambda}\ell^-$

Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either {Lambda}{sub c} or {Lambda} and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2 - 520) x 10{sup -8} are set on the branching fractions at the 90% confidence level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

A Search for the Rare Decay $B\rightarrow\gamma\gamma$

We report the result of a search for the rare decay B{sup 0} {yields} {gamma}{gamma} in 426 fb{sup -1} of data, corresponding to 226 million B{sup 0}{bar B}{sup 0} pairs, collected on the {Upsilon}(4S) resonance at the PEP-II asymmetric-energy e{sup +}e{sup -} collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21{sub -12}{sup +13} signal events with a statistical signficance of 1.9 {sigma}. This corresponds to a branching fraction {Beta}(B{sup 0} {yields} {gamma}{gamma}) = (1.7 {+-} 1.1(stat.) {+-} 0.2(syst.)) x 10{sup -7}. Based on this result, we set a 90% confidence level upper limit of {Beta}(B{sup 0} {yields} {gamma}{gamma}) < 3.2 x 10{sup -7}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of the B⁰→π⁻l⁺ν and B⁺→η (') l⁺ν branching fractions, the B⁰→π⁻l⁺ν and B⁺→ηl⁺ν form-factor shapes, and determination of |V ub |

We report the results of a study of the exclusive charmless semileptonic decays, B⁺→η (') l⁺ν and B⁰→π⁻l⁺ν, undertaken with approximately 464×10⁶ BB¯¯ pairs collected at the Υ(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B⁺→ηl⁺ν and B⁰→π⁻l⁺ν decays in three and 12 bins of q², respectively, from which we extract the f+(q²) form-factor shapes and the total branching fractions B(B⁺→ηl⁺ν)=(0.36±0.05 stat ±0.04 syst )×10⁻⁴ and B(B⁰→π⁻l⁺ν)=(1.42±0.05 stat ±0.07 syst )×10⁻⁴. We also measure B(B+→η'l⁺ν)=(0.24±0.08 stat ±0.03 syst )×10⁻⁴. We obtain values for the magnitude of the CKM matrix element |Vub| using three different QCD calculations.

del Amo Sanchez, P.↗
DOE OSTI2010

Observation of new resonances decaying to D{pi} and D{sup *}{pi} in inclusive e{sup +}e{sup -} collisions near {radical}(s)=10.58 GeV

We present a study of the D{sup +}{pi}{sup -}, D{sup 0}{pi}{sup +}, and D*{sup +}{pi}{sup -} systems in inclusive e{sup +}e{sup -}{yields}c{bar c} interactions in a search for new excited D meson states. We use a data set, consisting of {approx}454 fb{sup -1}, collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. We observe, for the first time, candidates for the radial excitations of the D{sup 0}, D*{sup 0}, and D*{sup +}, as well as the L=2 excited states of the D{sup 0} and D{sup +}, where L is the orbital angular momentum of the quarks.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Search for B{sup +} meson decay to a{sub 1}{sup +}(1260)K{sup *0}(892)

We present a search for the decay B{sup +}{yields}a{sub 1}{sup +}(1260)K{sup *0}(892). The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represent 465x10{sup 6}BB pairs produced in e{sup +}e{sup -} annihilation at the energy of the {Upsilon}(4S). We find no significant signal and set an upper limit at 90% confidence level on the product of branching fractions B(B{sup +}{yields}a{sub 1}{sup +}(1260)K{sup *0}(892))xB(a{sub 1}{sup +}(1260){yields}{pi}{sup +}{pi}{sup -}{pi}{sup +}) of 1.8x10{sup -6}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Correlated leading baryon-antibaryon production in e{sup +}e{sup -}{yields}cc{yields}{Lambda}{sub c}{sup +}{Lambda}{sub c}{sup -}X

We present a study of 649{+-}35 e{sup +}e{sup -}{yields}cc events produced at {radical}(s){approx_equal}10.6 GeV containing both a {Lambda}{sub c}{sup +} baryon and a {Lambda}{sub c}{sup -} antibaryon. The number observed is roughly 4 times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and c are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6{+-}0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗