In a sample of 467 million $B\overline B$ pairs collected with the BABAR detector at the PEP-II collider at SLAC we have observed the decay $\overline{B}^0\rightarrowΛ_c^+{\overline p} π^0$ and measured the branching fraction to be $(1.94\pm0.17 \pm 0.14 \pm 0.50)\times 10^{-4}$, where the uncertainties are statistical, systematic, and the uncertainty on the $Λ_c^+\rightarrow p {K^-} π^+$ branching fraction, respectively. We determine an upper limit of $1.5\times 10^{-6}$ at $90\%$ C.L. for the product branching fraction ${\cal B} (\overline{B}^0\rightarrow Σ_c^+(2455)\overline p)\times{\cal B} (Λ_c^+\rightarrow p K^- π^+)$. Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon-antibaryon pair.
Due to an excellent mass resolution and a large amount of available data, the CDF experiment, located at the Tevatron proton-antiproton accelerator, allows the precise measurement of spectroscopic properties, like mass and decay width, of a variety of states. This was exploited to examine the first orbital excitations of the Lambdac baryon, the resonances Lambdac(2595) and Lambdac(2625), in the decay channel Lambdac+ pi+ pi-, as well as the Lambdac spin excitations Sigmac(2455) and Sigmac(2520) in its decays to Lambdac+ pi- and Lambdac+ pi+ final states in a data sample corresponding to an int…
Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter alpha(Lambdac) in Lambdac --> Lambda pi decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter : A = [alpha(Lambdac)+alpha(antiLambda_c)]/[alpha(Lambdac)-alpha(antiLambda_c)]. We obtain alpha(Lambdac)=-0.78+-0.16+-0.13 and A = -0.07+-0.19+-0.12 where errors are statistical and systematic.
This paper describes an experimental search for antiproton decay at the Fermilab Antiproton Accumulator. The E868 (APEX) experimental setup is described. The APEX data is expected to be sensitive to antiproton decay if the antiproton lifetimes is less than a few times 100 000 years.
We report on the analyses of the baryonic B decays B0bar -> LambdaC+ p- p+ p- and B- -> SigmaC++ p- pi- pi-. The underlying data sample consists of 470 x 10^6 BBbar pairs generated in the process e+e- -> Y(4S) and collected with the BaBar detector at the PEP-II storage ring at SLAC. We find BR(B0bar -> LambdaC+ p- p+ p-) x BR(LambdaC+ -> p+ K- pi+) / 5% < 6.2 x 10^(-6) @ CL=90% and BR(B- -> SigmaC++ p- pi- pi-) = [2.98 +/- 0.16(stat) +/- 0.15(syst) +/- 0.77(LambdaC+)] x 10^(-4), where the last error is due to the uncertainty in BR(LambdaC+ -> p+ K- pi+). The data suggest the existence of reson…
A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on thirteen antiproton decay modes. The results include the first explicit experimental limits on the muonic decay modes of the antiproton, and the first limits on the decay modes e- gamma gamma, and e- omega. The most stringent limit is for the decay mode pbar-> e- gamma. At 90% C.L. we find that tau/B(pbar-> e- gamma) > 7 x 10^5 yr. The most stringent limit for decay modes with a muon in the final state is for the decay pbar-> mu- gamma. At 90% C.L. we find that tau/B(pbar-> mu- gamma) > 5 x…
The Xi(1690)0 resonance is observed in the Lambda anti-K0 channel in the decay Lambdac+ --> Lambda anti-K0 K+, from a data sample corresponding to a total integrated luminosity of ~ 200 fb-1 recorded by the Babar detector at the PEPII asymmetric-energy e+ e- collider operating at ~ 10.58 GeV and ~ 10.54 GeV center-of-mass energies. A fit to the Dalitz plot intensity distribution corresponding to the coherent superposition of amplitudes describing Lambda a0(980)+ and Xi(1690)0 K+ production yields mass and width values of 1684.7 +/- 1.3 (stat.) +2.2 -1.6 (syst.) MeV/c2, and $8.1 +3.9 -3.5 (stat…
We present measurements of branching fractions of $B^0$ decays to multi-body final states containing protons, based on 232 million $Υ(4S)\to B\bar{B}$ decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy $B$ factory. We measure the branching fractions ${\cal B}(B^0 \to \bar{D}^0\proton\antiproton)=(1.13\pm0.06\pm0.08)\times 10^{-4}$, ${\cal B}(B^0 \to \bar{D}^{*0}\proton\antiproton)=(1.01\pm0.10\pm0.09)\times 10^{-4}$, ${\cal B}(B^0 \to D^{-}\proton\antiprotonπ^+)=(3.38\pm0.14\pm0.29)\times 10^{-4}$, and ${\cal B}(B^0 \to D^{*-}\proton\antiprotonπ^+)=(4.81\pm0.22\pm0.4…
A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on six antiproton decay modes which contain a final-state muon. At the 90% C.L. we find that tau/B(mu gamma) > 5.0 x 10^4 yr, tau/B(mu pi0) > 4.8 x 10^4 yr, tau/B(mu eta) > 7.9 x 10^3 yr, tau/B(mu gamma gamma) > 2.3 x 10^4 yr, tau/B(mu K0S > 4.3 x 10^3 yr, and tau/B(mu K0L) > 6.5 x 10^3 yr.
We report the measurement of the baryonic B decay B- -> SigmaC++ p- pi- pi-. Using a data sample of 467*10^6 B B-bar pairs collected with the BaBar detector at the PEP-II storage ring at SLAC, the measured branching fraction is (2.98 +/- 0.16 (stat) +/- 0.15 (syst) +/- 0.77 (LambdaC+))*10^{-4}, where the last error is due to the uncertainty in the branching fraction of the decay LambdaC+ -> p+ K- pi+. The data suggest the existence of resonant subchannels B- -> LambdaC(2595)+ p- pi- and, possibly, B- -> SigmaC++ anti-Delta-- pi-. We see unexplained structures in m(SigmaC++ pi- pi-) at 3.25 GeV…
We report the observation of the baryonic B-decay B0bar -> Lambda_c^+ antiproton K^- pi^+, excluding contributions from the decay B0bar -> Lambda_c^+ anti-Lambda K^-. Using a data sample of 467*10^6 BBbar pairs collected with the BABAR detector at the PEP-II storage ring at SLAC, the measured branching fraction is (4.33 +/- 0.82_stat +/- 0.33_syst +/- 1.13_Lambda_c^+)*10^-5. In addition we find evidence for the resonant decay B0bar -> Sigma_c(2455)^++ antiproton K^- and determine its branching fraction to be (1.11 +/- 0.30_stat +/- 0.09_syst +/- 0.29_Lambda_c^+)*10^-5. The errors are statistic…
Using events in which one of two neutral B mesons from the decay of an Y(4S) meson is fully reconstructed, we determine parameters governing decay (ΔΓ_d/Γ_d), CP and T violation (|q/p|), and CP and CPT violation (Rez,Imz). The results, obtained from an analysis of 88 million Y(4S) decays recorded by BABAR, are -- sgn(Re(lambdaCP))ΔΓ_d/Gamma_d = -0.008 +- 0.037 +- 0.018 [ -0.084, 0.068 ] |q/p| = 1.029 +- 0.013 +- 0.011 [ 1.001, 1.057 ] Re(lambdaCP)/|lambdaCP| Rez = 0.014 +- 0.035 +- 0.034 [ -0.072, 0.101 ] Imz = 0.038 +- 0.029 +- 0.025 [ -0.028, 0.104 ]. -- The values inside square brackets ind…
We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case where the Higgs bosons decay to tau lepton pairs, using 1.8 inverse fb of integrated luminosity of proton-antiproton collisions recorded by the CDF II experiment at the Fermilab Tevatron. Studying the observed mass distribution in events where one or both tau leptons decay leptonically, no evidence for a Higgs boson signal is observed. The result is used to infer exclusion limits in the two-dimensional parameter space of tan beta versus m(A).
We present a measurement of the coefficient alpha_2 of the leptonic polar-angle distribution from W boson decays, as a function of the W transverse momentum. The measurement uses an 80+/-4 pb^{-1} sample of proton-antiproton collisions at sqrt{s}=1.8 TeV collected by the CDF detector and includes data from both the W->e+nu and W->mu+nu decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the Standard Model expectation, whereby t…
We have performed a search for radiative b-hadron decays using events produced in proton-antiproton collisions at sqrt(s) = 1.8 TeV and collected by the Collider Detector at Fermilab. The decays we considered were B_d -> K*0(-> K+ pi-) gamma, B_s -> phi(-> K+ K-) gamma, Lambda_b -> Lambda(-> p pi-) gamma, and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified by an electron-positron pair produced through the external …
We present searches for charged Higgs production in decays of top quarks and also pair production of doubly charged Higgs boson decaying to di-tau, di-muon, and muon + tau final states. The searches are performed in proton-antiproton collisions at sqrt{s} = 1.96 TeV using an integrated luminosity of up to 7 fb-1 collected by the CDF and D0 experiments at the Fermilab Tevatron Collider. We find no evidence for charged Higgs production and set limits on the production cross-section for a variety of theoretical models. This represents the first search for pair production of doubly-charged Higgs b…
A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on fifteen antiproton decay modes. The results are used to place limits on the characteristic mass scale Mx that could be associated with CPT-violation accompanied by baryon number violation.
We present the first measurement of the A_2 and A_3 angular coefficients of the W boson produced in proton-antiproton collisions. We study W-> e+nu and W-> mu+nu candidate events produced in association with at least one jet at CDF, during Run Ia and Run Ib of the Tevatron at sqrt(s)=1.8 TeV. The corresponding integrated luminosity was 110 pb^-1. The jet balances the transverse momentum of the W and introduces QCD effects in W boson production. The extraction of the angular coefficients is achieved through the direct measurement of the azimuthal angle of the charged lepton in the Collins-Soper…
We present the results of a search for the spin-singlet P-wave state hc(1 1P1) of charmonium formed through proton-antiproton annihilation at Fermilab experiment E835. The decay channels whjich were studied were ppbar -> J/psi + X -> e^+e^- + X, ppbar -> J/psi + pi0 -> e^+e^- + 2gamma, ppbar -> J/psi + pi0pi0 -> e^+e^- + 4gamma, and the neutral channel ppbar -> eta_c gamma -> (2gamma) gamma. The decay ppbar -> J/psi gamma -> e^+e^- gamma, into which 1P1 decay is forbidden by C-parity conservation, was also examined for comparison The 90% confidence upper limits for the decay channels studied i…
We present two measurements of the ttbar production cross section in collisions of protons and antiprotons at sqrt{s}=1.96 TeV. We analyze a dataset of 310+/-20 pb-1 collected with the CDF2 detector. In the first measurement, we select events with six to eight jets, at least one of which having a displaced secondary vertex, little or no missing transverse energy and optimized kinematical criteria consistent with the ttbar all-hadronic decay channel. In the second measurement, we select events with four or more jets, at least one of which having a displaced secondary vertex, high missing transv…
In inclusive P-wave charmonium decay, to cancel infrared divergence in the colour singlet contribution requires the inclusion of the colour octet which becomes degenerate with the former in the infrared limit. In the corresponding exclusive decay, such an infrared divergence does not exist. On this ground, it becomes doubtful whether the colour octet is needed in exclusive reactions. A contradiction in the underlying picture, however, would result once all strong decay channels are summed. We provide an answer to this question in support of the colour octet with theoretical arguments as well a…
We review recent experimental results on Bd and Bs mesons decays by the BaBar and Belle experiments. These include measurements of the color-suppressed decays B0bar to D(*)0h0, h0=pi0, eta, etaprime, omega, observation of the baryonic decay B0bar to Lambdac+ Lambdabar K-, measurements of the charmless decays B to eta h, h=K, pi, B to Kpi and observation of CP eigenstates in the Bs decays: B0s to J/psi f0(980), B0s to J/psi f0(1370) and B0s to J/psi eta. The theoretical implications of these results will be considered.
We present the results of a search for pair production of a new heavy top-like quark t' decaying to a W boson and another quark using the CDF II detector in Run II of the Tevatron proton-antiproton collider. Using a data sample corresponding to 760 pb^-1 of integrated luminosity, we fit the observed spectrum of total transverse energy and reconstructed t' quark mass to a combination of standard model processes and t' pair production. We see no evidence for t' pair production, and we infer a lower limit of 256 GeV/c^2 on the mass of the t' at 95% C.L. assuming standard strong couplings for the …
We present the results of a search for anomalous resonant production of tau lepton pairs with large invariant mass, the first such search using the CDF II Detector in Run II of the Tevatron $p\bar{p}$ collider. Such anomalous production could arise from various new physics processes. In a data sample corresponding to 195 pb$^{-1}$ of integrated luminosity we predict 2.8$\pm$0.5 events from Standard Model background processes and observe 4. We use this result to set limits on the production of heavy scalar and vector particles decaying to tau lepton pairs.
We comment on the quantum numbers and decay channels of the possible proton antiproton bound state observed by BES Collaboration. Based on the general symmetry consideration and available experimental information, we conclude that the quantum number of this state is very likely to be $J^{PC}=0^{-+}, I^G=0^+$, which can not decay into final states $π^+π^-, 2π^0, K{\bar K}, 3π$. Besides its dissociation into $p\bar p$, the other important mesonic decay modes could be $ηππ$, $η'ππ$, $ηηη$, $4π$, $K{\bar K}π$, $ηK{\bar K}$, $K\bar K ππ$, 6$π$. Experimental search of this signal in these meson fina…
We present a search for the standard model Higgs boson produced with a Z boson in 4.1 fb^-1 of data collected with the CDF II detector at the Tevatron. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electrons or muons, we set 95% credibility level upper limits on the ZH production cross section times the H -> b bbar branching ratio. Improved analysis methods enhance signal sensitivity by 20% relative to previous searches beyond the gain due to the larger data sample. At a Higgs boson mass of 115 GeV/c^2 we set a limit of 5.9 times the standard …
The results of several studies of charmed mesons and baryons at BABAR are presented. First, searches for the rare decays D0 --> l+ l- are presented and new upper limits on these processes are established. Second, a measurement of the branching fraction of the isospin-violating hadronic decay Ds*(2112)+ --> Ds+ pi0 relative to the radiative decay Ds*(2112)+ --> Ds+ gamma is made. Third, the decays of DsJ*(2317)+ and DsJ(2460)+ mesons are studied and ratios of branching fractions are measured. Fourth, Cabibbo-suppressed decays of the Lambdac+ are examined and their branching fractions measured r…
We describe a measurement of the top quark mass from events produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. We identify top-antitop candidates where both W bosons from the top quarks decay into leptons (electron, muon, or tau plus neutrino) from a data sample of 360 inverse picobarns. The top quark mass is reconstructed in each event separately by three different methods, which draw upon simulated distributions of the neutrino pseudorapidity, top-antitop longitudinal momentum, or neutrino azimuthal angle in order to extr…
We have compared the proton and antiproton angular distributions in 117 million Xi-minus -> Lambda + pi-minus -> proton + pi-minus + pi-minus and 41 million anti-Xi-minus -> anti-Lamba + pi-plus -> antiproton + pi-plus + pi-plus decays using a subset of the data from the HyperCP experiment (E871) at Fermilab. We find no evidence of CP violation, with the direct-CP-violating parameter $A_{ΞΛ} = \frac{α_Ξα_Λ - \barα_Ξ\barα_Λ}{α_Ξα_Λ + \barα_Ξ\barα_Λ} = [0.0+/-5.1(stat)+/-4.4(syst)]{\times}10^{-4}$.
We present a search for the rare radiative decay \wpigamma\ using data corresponding to an integrated luminosity of 4.3 \invfb\ of proton-antiproton collisions at a center of mass energy of 1.96 TeV collected by the CDF experiment at Fermilab. As no statistically significant signal is observed, we set a 95% confidence level upper limit on the relative branching fraction \bratio\ at $6.4\times 10^{-5}$, a factor of 10 improvement over the previous limit.
Using data from proton-antiproton collisions at Ecms=1.96 TeV recorded by the CDF II detector at the Fermilab Tevatron, evidence for the excited resonance state Lambda_b* is presented in its Lambda_b0 pi+ pi- decay, followed by the Lambda_b0 -->Lambda_c+ (-->proton K- pi+) pi- decays. The analysis is based on a data sample corresponding to an integrated luminosity of 9.6/fb collected by an online event selection based on charged-particle tracks displaced from the proton-antiproton interaction point. The significance of the observed signal is 3.5 Gaussian sigmas. The mass of the observed state …
The Tevatron proton-antiproton collider at Fermilab with its centre of mass energy of 1.96 TeV allows for pair production of top quarks and the study of top quark decay properties. This report reflects the current status of measurements of the W boson helicity in top quark decays and the ratio of top quark branching fractions as well as searches for neutral current top quark decays and pair production of fourth generation t' quarks, performed by the D0 Collaboration utilising datasets of up to 5.4/fb.
We search for pair production of doubly charged Higgs particles followed by decays into electron-tau and muon-tau pairs using data (350 inverse picobarns) collected from proton-antiproton collisions at 1.96 TeV by the CDF II experiment. We search separately for cases where three or four final-state leptons are detected, and combine results for exclusive decays to left-handed electron-tau (muon-tau) pairs. We set a lower mass limit of 114 (112) GeV/cc at the 95% confidence level for left-handed doubly charged Higgs.
Using 3.08 million psi(2S) decays observed in e^+e^- collisions by the CLEO detector, we present the results of a study of the psi(2S) decaying into baryon-antibaryon final states. We report the most precise measurements of the following eight modes: proton-antiproton, lambda-antilambda, Xi^- antiXi^-, Xi^0-antiXi^0 (first observation), Sigma+-antiSigma^+ (first observation), and Sigma^0-antiSigma^0, and place upper limits for the modes, Xi^0*-antiXi^0* and Omega^- antiOmega^-.
Fully reconstructed top-antitop-events are used to determine the fractions of right-handed and longitudinally polarized W bosons produced in top-quark decays. The helicity fractions are sensitive to the couplings and the Dirac structure of the Wtb vertex. This paper reports measurements of the W-boson helicity fractions from two different methods using data corresponding to an integrated luminosity of 1.9 fb-1 of proton-antiproton collisions collected by the CDF II detector operating at the Fermilab Tevatron.
We present the first measurement of the CP violating charge asymmetry in $B^\pm \to μ^\pm ν_μ{D}^0$ decays using the full Run II integrated luminosity of 10.4 fb$^{-1}$ in proton-antiproton collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure a difference in the yield of $B^-$ and $B^+$ mesons in these decays by fitting the reconstructed invariant mass distributions. This results in an asymmetry of $A^{μD^{0}} =\left[ -0.14 \pm 0.20 \right]\%$, which is consistent with standard model predictions.
Important information about the dynamics of hadron production can be obtained by the study of particle correlations. More than 16 million hadronic Z0 decays and several thousand W+W- events have been recorded from the four LEP collaborations between 1989 and 2000. Recently, in Z0 decays, new results of Bose-Einstein correlations in pairs of pions and Fermi-Dirac correlations for antiproton pairs were reported. In fully-hadronic W+W- decays particle correlations were used to study whether the two W bosons decay independently.
The lifetime of the $B_c^{-}$ meson is measured using 272 exclusive $B_{c}^{-} \to J/ψ(\to μ^+μ^-) π^-$ decays reconstructed in data from proton-antiproton collisions corresponding to an integrated luminosity of 6.7 fb$^{-1}$ recorded by the CDF II detector at the Fermilab Tevatron. The lifetime of the $B_c^{-}$ meson is measured to be $τ$($B_c^{-}$) = 0.452 $\pm$ 0.048(stat) $\pm$ 0.027(syst) ps. This is the first measurement of the $B_c^{-}$ meson lifetime in a fully-reconstructed hadronic channel, and it agrees with previous results and has comparable precision.
A search for Z boson decays to pairs of b-quark jets has been performed in the full dataset collected with the CDF detector at the Tevatron proton-antiproton collider. After the selection of a pure sample of bb events by means of the identification of secondary vertices from b-quark decays, we have used two kinematic variables to further discriminate the electroweak bb production from QCD processes, and sought evidence for the Z decay in the dijet invariant mass distribution. An absolute background prediction allows the extraction of an excess of events inconsistent with the background predict…
We report the first observation of exclusive decays of the type B to D^* N anti-N X, where N is a nucleon. Using a sample of 9.7 times 10^{6} B-Bbar pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B^0 \to D^{*-} proton antiproton π^+) = ({6.5}^{+1.3}_{-1.2} +- 1.0) \times 10^{-4} and B(B^0 \to D^{*-} proton antineutron) = ({14.5}^{+3.4}_{-3.0} +- 2.7) times 10^{-4}. Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.
The present day experimental data on the $X(3872)$ decays do not allow to make clear conclusions on the dominating structure of this state. We discuss here an alternative way to study its structure by means of the two-step $\bar D^*$ (or $D$) production in $\bar p A$ reactions. If this process is mediated by $X(3872)$, the characteristic narrow peaks of the $\bar D^*$ (or $D$) distributions in the light cone momentum fraction at small transverse momenta will appear. This would unambiguously signal the $D \bar D^*$ + c.c. molecular composition of the $X(3872)$ state.
We present a measurement of the time-integrated flavor-specific semileptonic charge asymmetry in the decays of Bs mesons that have undergone flavor mixing, a^s_ls, using B_s^0 (barB_s^0) -> D_s^-/+ mu^+/- X decays, with D_s^-/+ -> phi pi^-/+ and phi K^+ K^-, using 10.4 fb^-1 of proton-antiproton collisions collected by the D0 detector during Run II at the Fermilab Tevatron Collider. A fit to the difference between the time-integrated D_s^-$ and D_s^+ mass distributions of the B_s^0 and barB^0_s candidates yields the flavor-specific asymmetry a^s_ls = [-1.12 pm 0.74 (stat) +/-0.17 (syst)]% whic…
The neutron fraction in the very high energy cosmic rays near the Greisen-Zatsepin-Kuzmin (GZK) cutoff energy is analyzed by taking into account the time dilation effect of the neutron decays and also the pion photoproduction behaviors above the GZK cutoff. We predict a non-trivial neutron fraction above the GZK cutoff and a negligibly small neutron fraction below. However, there should be a large antiproton fraction in the high energy cosmic rays below the GZK cutoff in several existing models for the observed cosmic-ray events above and near the GZK cutoff. Such a large antiproton fraction c…
We present a measurement of the direct $CP$-violating charge asymmetry in $D_s^\pm \to ϕπ^{\pm}$ decays where the $ϕ$ meson decays to $K^+K^-$, using the full Run II data set with an integrated luminosity of 10.4 fb$^{-1}$ of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. The normalised difference $A_{CP}$ in the yield of $D_s^+$ and $D_s^-$ mesons in these decays is measured by fitting the difference between their reconstructed invariant mass distributions. This results in an asymmetry of $A_{CP} =\left[ -0.38 \pm 0.27 \right]%$, which is the m…
We have performed a search for CP violation in a sample of Bs -> Ds mu X decays corresponding to $5$~fb$^{-1}$ of proton-antiproton collisions collected by the D0 detector in Run~II at the Fermilab Tevatron Collider. New physics in $B_s^0$ mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for $B_s^0\to \bar{B}_s^0$ oscillated states versus that for $\bar{B}_s^0\to {B}_s^0$. A fit to the decay-time distributions of the $B_s^0/\bar{B}_s^0$ candidates yields the flavor-specific asymmetry $a_{fs}^{s}=[-1.7\pm 9.1\m…
Recent rate measurements of B_s mesons and Lambda_b baryons produced in sqrt{s} = 1.96 TeV proton-antiproton and Upsilon(5S) electron-positron collisions are reviewed, including the first observations of six new decay modes: B_s -> D_s^+ K^- (CDF), B_s -> D_s^- D_s^+ (CDF), B_s -> D_{s1}^-(2536) mu^+ nu_mu X (DZero), B_s -> phi gamma (Belle), Lambda_b -> p pi^- (CDF), and Lambda_b -> p K^- (CDF). Also examined are branching-fraction measurements or limits for the B_s -> D_s^{(*)} D_s^{(*)} modes (Belle, CDF, and DZero), the B_s -> gamma gamma radiative penguin decay (Belle), and three two-body…
The decay $D_s^+\to p \bar p e^+ν_e$ with a proton-antiproton pair in the final state is unique in the sense that it is the only semileptonic baryonic decay which is physically allowed in the charmed meson sector. Its measurement will test our basic knowledge on semileptonic $D_s^+$ decays and the low-energy $p\bar p$ interactions. Taking into account the major intermediate state contributions from $η, η', f_0(980)$ and $X(1835)$, we find that its branching fraction is at the level of $10^{-9} \sim 10^{-8}$. The location and the nature of $X(1835)$ state are crucial for the precise determinati…
