Showing papers by "Sergio Grancagnolo published in 2005"
TL;DR: Fits to the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/c2 is required to describe the observed structure, and the presence of additional narrow resonances cannot be excluded.
Abstract: We study initial-state radiation events, $e^+e^- \to \gamma_{ISR}\pi^+\pi^-J/\psi$, with data collected with the BaBar detector. We observe an accumulation of events near 4.26 GeV/$c^2$ in the invariant-mass spectrum of $\pi^+\pi^-J/\psi$. Fits of the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/$c^2$ is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to 90 MeV/$c^2$, depending on the fit hypothesis.
562 citations
TL;DR: In this article, the decay of B{bar B} events collected at the BaBar detector at the PEP-II e{sup +}e{sup -} asymmetric energy storage ring was studied.
Abstract: The authors study the decay B{sup -} {yields} J/{psi}K{sup -}{pi}{sup +}{pi}{sup -} using 117 million B{bar B} events collected at the {Upsilon}(4S) resonance with the BaBar detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage ring. They measure the branching fractions {Beta}(B{sup -} {yields} J/{psi}K{sup -} {pi}{sup +}{pi}{sup -}) = (116 {+-} 7(stat.) {+-} 9(syst.)) x 10{sup -5} and {Beta}(B{sup -} {yields} X(3872)K{sup -}) x {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) = (1.28 {+-} 0.41) x 10{sup -5} and find the mass of the X(3872) to be 3873.4 {+-} 1.4MeV/c{sup 2}. They search for the h{sub c} narrow state in the decay B{sup -} {yields} h{sub c} K{sup -}, h{sub c} {yields} J/{psi}{pi}{sup +}{pi}{sup -} and for the decay B{sup -} {yields} J/{psi}D{sup 0}{pi}{sup -}, with D{sup 0} {yields} K{sup -}{pi}{sup +}. They set the 90% C.L. limits {Beta}(B{sup -} {yields} h{sub c}K{sup -}) x {Beta}(h{sub c} {yields} J/{psi}{pi}{sup +}{pi}{sup -}) < 3.4 x 10{sup -6} and {Beta}(B{sup -} {yields} J/{psi}D{sup 0}{pi}{sup -}) < 5.2 x 10{sup -5}.
346 citations
TL;DR: In this paper, the invariant mass distribution recoiling against fully reconstructed $J/psi$ decays, using 124 fb$^{-1}$ of data collected with a center-of-mass energy of 10.6 GeV with the BaBar detector.
Abstract: We study $e^+e^-\to J/\psi c\bar{c}$ by measuring the invariant mass distribution recoiling against fully reconstructed $J/\psi$ decays, using 124 fb$^{-1}$ of data collected with a center-of-mass energy of 10.6 GeV with the $BaBar$ detector. We observe signals for $\eta_c(1S)$, $\chi_{c0}$, and $\eta_c(2S)$ in the recoil mass distribution, thus confirming previous measurements. We measure $\sigma(e^+e^-\to J/\psi+c\bar{c}) {\cal B} (c\bar{c} \to >2 charged)$ to be $17.6\pm2.8 (stat)^{+1.5}_{-2.1}(syst)$ fb, $ 10.3\pm2.5(stat)^{+1.4}_{-1.8}syst)$ fb, and $16.4\pm3.7(stat)^{+2.4}_{-3.0}(syst)$ fb with $c\bar{c}=\eta_c(1S)$, $\chi_{c0}$, and $\eta_c(2S)$, respectively.
142 citations
TL;DR: In this article, the authors studied the BaBar process with a hard photon radiated from the initial state and measured the cross section for the process for center-of-mass energies from 0.6 to 4.5 $GeV/c^2.
Abstract: We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ and $K^+ K^- K^+ K^-$. We observe the $J/\psi$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/\psi (\to\mu^+\mu^-) \pi^+\pi^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/\psi\pi^+\pi^-$.
120 citations
TL;DR: A search for the nonconservation of lepton flavor number in the decay tau(+/-) --> mu(+ +/-) has been performed using the BABAR detector at the PEP-II storage ring and an upper limit on the branching ratio is set.
Abstract: A search for the nonconservation of lepton flavor number in the decay tau(+/-)->mu(+/-)gamma has been performed using 2.07 x 10(8) e(+)e(-)->tau(+)tau(-) events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of B(tau(+/-)->mu(+/-)gamma) < 6.8 x 10(-8) at 90% confidence level.
114 citations
TL;DR: In this paper, a Dalitz-plot analysis of the hadronic decays of charged B mesons to the final state K+/- pi-/+ pi+/- was presented.
Abstract: We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K+/- pi-/+ pi+/-. Using a sample of 226.0 +/- 2.5 million BBbar pairs collected by the BaBar detector, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for both charge conjugate decays. We present measurements of the corresponding branching fractions and their charge asymmetries that supersede those of previous BaBar analyses. We find the charge asymmetries to be consistent with zero.
98 citations
TL;DR: In this article, the authors measured the branching fraction for the radiative penguin process B -> X_s gamma from the sum of 38 exclusive final states, and presented fits to the photon spectrum and moments which gave the heavy-quark parameters m_b and mu_pi^2.
Abstract: Using 88.9 million BB events collected by the BaBar detector at the Y(4S), we measure the branching fraction for the radiative penguin process B -> X_s gamma from the sum of 38 exclusive final states. The inclusive branching fraction above a minimum photon energy E_gamma > 1.9 GeV is BF (b -> s gamma) = (3.27 +/- 0.18 (stat.) +0.55/-0.40 (syst.) +0.04/-0.09 (theory)) 10^-4. We also measure the isospin asymmetry between B^- -> X_s ubar gamma and B^0bar -> X_s dbar gamma to be Delta_0- = -0.006 +/- 0.058 (stat.) +/- 0.009 (syst.) +/- 0.024 (B^0bar / B^-). The photon energy spectrum is measured in the B rest frame, from which moments are derived for different values of the minimum photon energy. We present fits to the photon spectrum and moments which give the heavy-quark parameters m_b and mu_pi^2. The fitted parameters are consistent with those obtained from semileptonic B -> X_c l nu decays, and are useful inputs for the extraction of Vub from measurements of semileptonic B -> X_u l nu decays.
93 citations
TL;DR: In this paper, the BaBar detector was used to search for a charged partner of the X(3872) in the decay of the PEP-II e+e- asymmetric energy storage ring.
Abstract: We search for a charged partner of the X(3872) in the decay B --> X- K, X- --> J/psi pi- pi0, using 234 million BBbar events collected at the Y(4S) resonance with the BaBar detector at the PEP-II e+e- asymmetric-energy storage ring. The resulting product branching fraction upper limits are BR(B0 --> X- K+, X- --> J/psi pi- pi0) X- K0bar,X- --> J/psi pi- pi0) < 22 x 10(-6) at the 90% confidence level.
90 citations
TL;DR: In this paper, the decay of the BaBar detector was studied with a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the Ba-Bar detector and a branching fraction Br(B+ --> p pbar K+)=(67+/-05+/-04)x10^{-6)
Abstract: With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar We measure a branching fraction Br(B+ --> p pbar K+)=(67+/-05+/-04)x10^{-6} An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 143 to 200 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level
78 citations
TL;DR: In this article, the BABAR detector at the Stanford Linear Accelerator Center was used to measure the decay amplitudes for the flavor eigenmodes and observe strong phase differences indicative of final-state interactions.
Abstract: We present results on B -> J/yKp decays using e+e-annihilation data collected with the BABAR detector at the U(4S) resonance. The detector is located at the PEP-II asym.-energy storage ring facility at the Stanford Linear Accelerator Center. Using approx. 88*106 B-B pairs, we measure the decay amplitudes for the flavor eigenmodes and observe strong-phase differences indicative of final-state interactions with a significance of 7.6 std. deviations. We use the interference between the Kp S-wave and P-wave amplitudes in the region of the K*(892) to resolve the ambiguity in the detn. of these strong phases. We then perform an ambiguity-free measurement of cos2b using the angular and time-dependent asymmetry in B -> J/yK*0(KS0p0) decays. With sin2b fixed at its measured value and cos2b treated as an independent parameter, we find cos2b=2.72-0.79+0.50(stat)+-0.27(syst), detg. the sign of cos2b to be pos. at 86% C.L. [on SciFinder (R)]
72 citations
TL;DR: Results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates are presented and the amplitude of the CPasymmetry, sin2beta, is measured in agreement with the standard model expectation.
Abstract: We present results on time-dependent $CP$ asymmetries in neutral $B$ decays to several $CP$ eigenstates. The measurements use a data sample of about 227 million $\Upsilon$(4S) $\rightarrow B\overline{B}$ decays collected by the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. The amplitude of the CP asymmetry, sin2$\Beta$ in the Standard Model, is derived from decay-time distributions from events in which one neutral $B$ meson is fully reconstructed in a final state containing a charmonium meson and the other $B$ meson is determined to be either a $B^0$ or $\overline{B}^0$ from its decay products. We measure sin2$\Beta$ = 0.722 $\pm$ 0.040 (stat.) $\pm$ 0.23 (syst.) in agreement with the Standard Model expectation.
TL;DR: A measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase gamma through a Dalitz analysis of neutral D decays to K0(S)pi-pi+ in the processes B+/- -->D*K+/-, D*-->Dpi0, Dgamma is reported on.
Abstract: We report on a measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase gamma through a Dalitz analysis of neutral D decays to K0(S)pi-pi+ in the processes B+/- -->D*K+/-, D*-->Dpi0, Dgamma. Using a sample of 227 x 10(6) BB pairs collected by the BABAR detector, we measure the amplitude ratios r(B)=0.12+/-0.03+/-0.04 and r*(B)=0.17+/-0.10+/-0.03+/-0.03, the relative strong phases delta(B)=(104+/-45(+17+16)(-21-24))degrees and delta*(B)=(-64+/-41(+14)(-12)+/-15) degrees between the amplitudes A(B- -->D*0K-) and A(B- -->D*0)K-), and gamma=(70+/-31(+12+14)(-10-11))degrees. The first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the Dalitz model uncertainty. The results for the strong and weak phases have a twofold ambiguity.
TL;DR: Measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson are reported.
Abstract: We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/{psi}, {psi}(2S) and {chi}{sub c1} and the light meson is either K or K*. We use a sample of about 124 million B{bar B} pairs collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.
TL;DR: In this article, the authors search for the rare flavor-changing neutral-current decay in a data sample of $82.1$ collected with the BABAR detector at the PEP-II $B$-factory.
Abstract: We search for the rare flavor-changing neutral-current decay ${B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{
u}\overline{\ensuremath{
u}}$ in a data sample of $82\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the BABAR detector at the PEP-II $B$-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-$B$ decay. Using these two independent samples we obtain a combined limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{
u}\overline{\ensuremath{
u}})l5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at the 90% confidence level. In addition, by selecting for pions rather than kaons, we obtain a limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{
u}\overline{\ensuremath{
u}})l1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ using only the hadronic $B$ reconstruction method.
TL;DR: In this paper, a measurement of the parameters of the Υ(10580) resonance based on a dataset collected with the BABAR detector at the SLAC PEP-II asymmetric B factory is presented.
Abstract: We present a measurement of the parameters of the Υ(10580) resonance based on a dataset collected with the BABAR detector at the SLAC PEP-II asymmetric B factory. We measure the total width Γtot=(20.7±1.6±2.5) MeV, the electronic partial width Γee=(0.321±0.017±0.029) keV and the mass M=(10579.3±0.4±1.2) MeV/c2.
TL;DR: A Dalitz-plot analysis of B+-decays to the final state pi+-pi+- pi-+ using 210 fb^-1 of data recorded by the BABAR experiment at sqrt(s) = 10.58 GeV is presented in this paper.
Abstract: We present a Dalitz-plot analysis of charmless B+- decays to the final state pi+- pi+- pi-+ using 210 fb^-1 of data recorded by the BABAR experiment at sqrt(s) = 10.58 GeV. We measure the branching fractions B(B+- -> pi+- pi+- pi-+) = (16.2 +- 1.2 +- 0.9) x 10^-6 and B(B+- -> rho^0(770) pi+-) = (8.8 +- 1.0 +- 0.6 +0.1-0.7) x 10^-6. Measurements of branching fractions for the quasi-two-body decays B+- -> rho^0(1450) pi+-, B+- -> f_0(980) pi+- and B+- -> f_2(1270) pi+- are also presented. We observe no charge asymmetries for the above modes, and there is no evidence for the decays B+- -> chic0 pi+-, B+- -> f_0(1370) pi+- and B+- -> sigma pi+-.
TL;DR: In this article, a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*-+ pi+-, using approximately 232 million BBbar events recorded by the BABAR experiment at the PEP2 e+e- storage ring is presented.
Abstract: We present a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*-+ pi+-, using approximately 232 million BBbar events recorded by the BABAR experiment at the PEP2 e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi+- from the B decay and the low-momentum pi-+ from the D*-+ decay are used. % We measure the parameters related to 2beta+gamma to be a_D*pi=-0.034 +- 0.014 +- 0.009 and c_l_D*pi = -0.019 +- 0.022 +- 0.013. With some theoretical assumptions, we interpret our results in term of the lower limits |\sin(2beta+gamma)|> 0.62 (0.35) at 68% (90%) confidence level.
TL;DR: In this paper, the Cabibbo-Kobayashi-Maskawa matrix element |Vub| was determined based on the analysis of semileptonic B decays from a sample of 88 x 10(6) Gamma(4S) decays collected with the BABAR detector at the SLAC PEP-II e+e- storage ring.
Abstract: We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vub| based on the analysis of semileptonic B decays from a sample of 88 x 10(6) Gamma(4S) decays collected with the BABAR detector at the SLAC PEP-II e+e- storage ring. Charmless semileptonic B decays are selected using measurements of the electron energy and the invariant mass squared of the electron-neutrino pair. We obtain |Vub| =(3.95 +/- 0.26(+0.58)(-0.42) +/- 0.25) x 10(-3), where the errors represent experimental uncertainties, heavy quark parameter uncertainties, and theoretical uncertainties, respectively.
TL;DR: In this article, an analysis of exclusive charmless semileptonic B-meson decays based on 83x10{sup 6} BB pairs recorded with the BABAR detector at the {upsilon}(4S) resonance using isospin symmetry is presented.
Abstract: We present an analysis of exclusive charmless semileptonic B-meson decays based on 83x10{sup 6} BB pairs recorded with the BABAR detector at the {upsilon}(4S) resonance Using isospin symmetry, we measure branching fractions B(B{sup 0}{yields}{pi}{sup -}l{sup +}{nu})=(138{+-}010{+-}016{+-}008)x10{sup -4} and B(B{sup 0}{yields}{rho}{sup -}l{sup +}{nu})=(214{+-}021{+-}048{+-}028)x10{sup -4}, where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties We compare the measured distribution in q{sup 2}, the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V{sub ub}|=(382{+-}014{+-}022{+-}011{sub -052}{sup +088})x10{sup -3} from B{yields}{pi}l{nu}, where the fourth error reflects the uncertainty of the form-factor normalization
TL;DR: In this article, the authors search for strange pentaquark states that have been previously reported by other experiments and find no evidence for these states and set 95% confidence level upper limits on the number of Theta(1540)(+) and Xi(5)(1860)(--) pentaquarks produced per e(+)e(-) annihilation into qq and Gamma(4S) decay.
Abstract: We search for strange-pentaquark states that have been previously reported by other experiments--the Theta (1540)(+), Xi(5)(1860)(--), and Xi(5)(1860)(0)--in 123 fb(-1) of data recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring. We find no evidence for these states and set 95% confidence level upper limits on the number of Theta(1540)(+) and Xi(5)(1860)(--) pentaquarks produced per e(+)e(-) annihilation into qq and Gamma(4S) decay. For qq events the Theta(1540)(+) [Xi(5)(1860)(--)] limit is about 8 [4] times lower than the rates measured for ordinary baryons of similar mass.
TL;DR: In this paper, the authors measured the time-dependent asymmetry parameters in the two-body and three-body decay of the Bz-to-Kp-Km-KZ decay.
Abstract: We measure the time-dependent \CP asymmetry parameters in $\Bz\to\Kp\Km\KZ$ based on a data sample of approximately 227 million $B$-meson pairs recorded at the $\Upsilon(4S)$ resonance with the \babar\ detector at the \pep2\ $B$-meson Factory at SLAC. We reconstruct two-body \Bz decays to $\phi(1020)\KS$ and $\phi(1020)\KL$, and the three-body decay $\KKKs$ with $\phi(1020)\KS$ excluded. For the $\Bz\to\phi\KZ$ decays, we measure $\sin2\beta_\textrm{eff}(\phi\KZ) = \finalscb$. The $\Bz\to\Kp\Km\KS$ decays are dominated by $K^+K^-$ $S$-wave, as determined from an angular analysis; we measure $\sin2\beta_\textrm{eff}(\KKKs) = \finalstbkk$, where the last error is due to the uncertainty in the fraction of \CP-even contributions to the decay amplitude. We find no evidence for direct \CP violation.
TL;DR: Using an isospin analysis of B --> rhorho decays, the unitarity triangle parameter alpha is determined and the solution compatible with the standard model is alpha = (100 +/- 13) degrees.
Abstract: We present results from an analysis of B(0)B(0)--> rho(+)rho(-) using 232 x 10(6) Gamma (4S) --> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction f(L) = 0.978 +/- 0.014(stat) + 0.021 / -0.029(syst) and the CP-violating parameters S(L)= -0.33 +/- 0.24(stat) + 0.08 / -0.14(syst) and C(L)= -0.03 +/- 0.18(stat) +/- 0.09(syst). Using an isospin analysis of B --> rhorho decays, we determine the unitarity triangle parameter alpha. The solution compatible with the standard model is alpha = (100 +/- 13) degrees.
TL;DR: In this paper, the branching fraction B(B0-->pi(0)π(0))=(1.17+/-0.32+/- 0.10)x10(-6), and the asymmetry Cpi( 0)(pi(1))=-0.12+/-1.06+/-2.06.
Abstract: Based on a sample of 227 x 10(6) BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the branching fraction B(B0-->pi(0)pi(0))=(1.17+/-0.32+/-0.10)x10(-6), and the asymmetry Cpi(0)(pi(0))=-0.12+/-0.56+/-0.06. The B0-->pi(0)pi(0) signal has a significance of 5.0 sigma. We also measure B(B+-->pi(+)pi(0))=(5.8+/-0.6+/-0.4)x10(-6), B(B+-->K+pi(0))=(12.0+/-0.7+/-0.6)x10(-6), and the charge asymmetries Api(+)(pi(0))=-0.01+/-0.10+/-0.02 and AK+(pi(0))=0.06+/-0.06+/-0.01. Using isospin relations, we find an upper bound on the angle difference |alpha-alpha(eff)| of 35 degrees at the 90% C.L.
TL;DR: In this paper, a measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K* {sup 0}{gamma} decays with K*{sup 1 0], where the first error is statistical and the second systematic.
Abstract: We present a measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K*{sup 0}{gamma} decays with K*{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0} based on 232 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 In a sample containing 157 {+-} 16 signal decays, we measure S{sub K*{sup 0}{gamma}} = -021 {+-} 040 {+-} 005 and C{sub K*{sup 0}{gamma}} = -040 {+-} 023 {+-} 003, where the first error is statistical and the second systematic We also explore B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} decays with 11 < m{sub K{sub S}{sup 0}{pi}{sup 0}} < 18 GeV/c{sup 2} and find 59 {+-} 13 signal events with S{sub K{sub S}{sup 0}{pi}{sup 0}{gamma}} = 09 {+-} 10 {+-} 02 and C{sub K{sub S}{sup 0}{pi}{sup 0}{gamma}} = -10 {+-} 05 {+-} 02
30 Jun 2005
TL;DR: In this article, a lepton-tagged fully-inclusive measurement of the photon energy spectrum in the BaBar data set was presented. But the results were based on a BaBar set of 88.5 million pairs at the 4S resonance.
Abstract: We present preliminary results from a lepton-tagged fully-inclusive measurement of $B \to X_{s}\gamma$ decays, where $X_{s}$ is any strange hadronic state. Results are based on a BaBar data set of 88.5 million $B\bar{B}$ pairs at the $\Upsilon(4S)$ resonance. We present a reconstructed photon energy spectrum in the $\Upsilon(4S)$ frame, and partial branching fractions above minimum reconstructed photon energies of 1.9, 2.0, 2.1 and 2.2 GeV. We then convert these to measurements of partial branching fractions and truncated first and second moments of the true photon energy distribution in the B rest frame, above the same minimum photon energy values. The full correlation matrices between the first and second moments are included to allow fitting to any parameterized theoretical calculation. We also measure the direct CP asymmetry $A_{cp}(B \to X_{s+d}\gamma)$ (based on the charge of the tagging lepton) above a reconstructed photon energy of 2.2 GeV
TL;DR: In this paper, the authors measured the time-dependent $CP$ asymmetry parameters in the BABAR detector at the PEP-II $B$-meson factory at SLAC.
Abstract: We measure the time-dependent $CP$ asymmetry parameters in ${B}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{K}^{0}$ based on a data sample of approximately $227\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B$-meson pairs recorded at the $\ensuremath{\Upsilon}(4S)$ resonance with the BABAR detector at the PEP-II $B$-meson Factory at SLAC. We reconstruct two-body ${B}^{0}$ decays to $\ensuremath{\phi}(1020){K}_{S}^{0}$ and $\ensuremath{\phi}(1020){K}_{L}^{0}$, and the three-body decay ${K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0}$ with $\ensuremath{\phi}(1020){K}_{S}^{0}$ excluded. For the ${B}^{0}\ensuremath{\rightarrow}\ensuremath{\phi}{K}^{0}$ decays, we measure $\mathrm{sin} 2{\ensuremath{\beta}}_{\mathrm{eff}}(\ensuremath{\phi}{K}^{0})=+0.50\ifmmode\pm\else\textpm\fi{}0.25(\mathrm{stat}{)}_{\ensuremath{-}0.04}^{+0.07}(\mathrm{syst})$. The ${B}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0}$ decays are dominated by ${K}^{+}{K}^{\ensuremath{-}}$ $S$ wave, as determined from an angular analysis; we measure $\mathrm{sin} 2{\ensuremath{\beta}}_{\mathrm{eff}}({K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0})=+0.55\ifmmode\pm\else\textpm\fi{}0.22(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.11(CP)$, where the last error is due to the uncertainty in the fraction of $CP$-even contributions to the decay amplitude. We find no evidence for direct $CP$ violation.
TL;DR: A search for the decay B(-)--> tau(-)nu(tau) in a sample of 88.9 x 10(6) BB pairs recorded with the BABAR detector at the Stanford Linear Accelerator Center B factory finds no evidence of a signal and sets an upper limit on the branching fraction of B(B(-) --> t Tau(-) nu( tau) < 4.2 x 10(-4) at the 90% confidence level.
Abstract: We present a search for the decay B(-)--> tau(-)nu(tau) in a sample of 88.9 x 10(6) BB pairs recorded with the BABAR detector at the Stanford Linear Accelerator Center B factory. One of the two B mesons from the Gamma(4S) is reconstructed in a hadronic or a semileptonic final state, and the decay products of the other B in the event are analyzed for consistency with a B(-) --> tau(-)nu(tau) decay. We find no evidence of a signal and set an upper limit on the branching fraction of B(B(-) --> tau(-) nu(tau)) < 4.2 x 10(-4) at the 90% confidence level.
TL;DR: In this paper, the decay chain is fully reconstructed to measure the branching fraction product {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) x {Beta(D{subs}{sup+} [ϵ]-ϵ+ ϵ+ϵ] x ϵ ϵ + ϵ ≥ 0.38% where the first uncertainties are statistical and second systematic.
Abstract: The authors present measurements of the branching fractions {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) and {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}), based on 123 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} B factory. A partial reconstruction technique is used to measure {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) and the decay chain is fully reconstructed to measure the branching fraction product {Beta}(B{sup 0} {yields} D*{sup -} D*{sub s}{sup +}) x {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}). Comparing these two measurements provides a model-independent determination of the D{sub s}{sup +} {yields} {phi}{pi}{sup +} branching fraction. They obtain {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) = (1.88 {+-} 0.09 {+-} 0.17)% and {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) = (4.81 {+-} 0.52 {+-} 0.38)%, where the first uncertainties are statistical and the second systematic.
TL;DR: In this article, a search for the CP asymmetry in the singly Cabibbo-suppressed decays was performed on a data sample of 79.9 fb$^{-1} recorded by the BABAR detector.
Abstract: We report on a search for the CP asymmetry in the singly Cabibbo-suppressed decays $D^+ \to K^-K^+\pi^+$ and in the resonant decays $D^+ \to \phi\pi^+$ and $D^+ \to \overline{K}^{\star0}K^+$ based on a data sample of 79.9 fb$^{-1}$ recorded by the BABAR detector. We use the Cabibbo-favored $D_s^+ \to K^-K^+\pi^+$ branching fraction as normalization in the measurements to reduce systematic uncertainties. The CP asymmetries obtained are $A_{CP}(K^-K^+\pi^{\pm}) = (1.4 \pm 1.0 (stat.) \pm 0.8 (syst.) \times 10^{-2}, A_{CP}(phi pi) = (0.2 +/- 1.5 (stat.) +/- 0.6 (syst.) x 10^-2$, and $A_{CP}(\overline{K}^{\star0} K^{\pm}) = (0.9 \pm 1.7 (stat.) \pm 0.7 (syst.) \times 10^{-2}$. The relative branching fraction $\Gamma(D^+ \to K^-K^+\pi^+)/\Gamma(D^+ \to K^-\pi^+\pi^+)$ is also measured and is found to be $(10.7 \pm 0.1 (stat.) \pm 0.2 (syst.) \times 10^{-2}$.