Francesco Renga
We will present the most recent results from the BABAR Collaboration concerning New Physics searches in rare B and Lepton Flavour Violating (LFV) decays, including b --> s transitions, purely leptonic B decays and LFV tau decays.
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We present recent measurements of hadronic cross-sections from the BaBar experiment and report preliminary results on searches for pentaquark states.
We present recent BABAR results on searches for dark photons, long-lived scalar particles and new pi0-like particles.
Results are presented from the CLEO, BaBar and Belle collaborations on searches for lepton-number-violating B decays.
In this paper we present two searches for new physics in Upsilon(3S) decays collected by the BABAR detector. We search for charged lepton-flavour violating decays of the Upsilon(3S), which are unobservable in the Standard Model but are predicted to occur in several beyond-the-Standard Model scenarios. We also search for production of a light Higgs or Higgs-like state produced in radiative decays of the Upsilon(3S) and decaying to muon pairs.
Using data collected with the BaBar detector at PEP-II at SLAC, we report on several tau lepton measurements that are used to determine the modulus of the Cabibbo-Kobayashi-Maskawa matrix element Vus, and to check the Standard Model predictions of lepton universality and CPT conservation.
The BaBar experiment recorded 471 x 10^6 BBbar pairs at the Y(4S) resonance (corresponding to an integrated luminosity of 429 fb^-1). We present here a selection of recent results from the BaBar collaboration: search for lepton-number violation in the decay B^+ -> h^- l^+ l^+, search for lepton-flavor violation in B^+/- -> h^+/- tau l and CP-violation in tau^- -> pi^- KS (>= 0 pi^0) nu_tau.
This paper presents the results of inclusive searches for the strange pentaquark states $Θ^+(1540)$, $Ξ_5^{--}(1860)$ and $Ξ_5(1860)^{0}$ as well as the anti-charm pentaquark state $Θ_c(3099)^{0}$ in a dataset of 123.4 fb$^{-1}$ collected on and 40$ $MeV below the $Υ(4S)$ resonance by the BABAR detector at the $e^+e^-$ PEPII storage rings. No evidence for the pentaquark states is found and upper limits on the rate of $Θ^+(1540)$ and $Ξ_5^{--}(1860)$ production in $e^+e^-$ annihilation are obtained.
I present three recent results from searches for exotic physics at the BaBar/PEP-II B-factory. These results span many of the samples produced at the B-factory, including B mesons, tau leptons, and Upsilon(3S) mesons. We have searched for CPT-violation in B mixing and find no significant deviation from the no-violation hypothesis. We have also searched for lepton-flavor-violating decays of the tau using tau- -> omega l- and tau- -> l+ l- l+ and their charge conjugates. We find no evidence for these processes and set upper limits on their branching fractions. Finally, we have searched for a low…
We describe measurements of CP and CPT violation parameters in B^0B^0bar oscillations, performed at BaBar by using BBbar events collected at the Y(4S) mass peak. These are obtained from two different B-reconstruction methods, namely: searching for two inclusive semileptonic B^0 decays in an event or partially reconstructing one of the B^0 mesons in the D* l nu_l channel. The results are in agreement with one another and with the most recent theoretical calculations in the Standard Model scenario.
The BaBar experiment has recently obtained some important results in the search for new physics in leptonic and lepton flavor violating decays, exploiting the complete datasets collected at the $Υ(4S)$, $Υ(3S)$ and $Υ(2S)$ energies. In particular, new limits on the ratio $Γ(Υ(1S)\toτ^+τ^-)/Γ(Υ(1S)\toμ^+μ^-)$, on lepton flavor violating decays of the $Υ(3S)$ and $Υ(2S)$, and on $τ$ decays to three charged leptons or $τ\to e/μγ$ are presented.
Results of recent searches for new physics in CP violation in charm decays from the BABAR experiment are presented. These results include a measurement of $D^0$ - $\bar{D}^0$ mixing and searches for CP violation in two-body $D^0$ decays, a search for CP violation in the charm decays $D^{\pm} \to K^0_S K^{\pm}$ and $D^{\pm}_s \to K^0_S K^{\pm}$, $K^0_S π^{\pm}$, and a search for direct CP violation in the singly-Cabibbo suppressed $D^{\pm} \to K^+ K^- π^{\pm}$ decays. These studies are based on the final dataset collected by BABAR at the PEP-II B factory at SLAC in the period 1999-2008. No evid…
Several new-physics (NP) models predict the existence of low-mass Higgs states and light dark matter candidates. Previous BABAR searches have given null results for these new states and have excluded large regions of the NP models parameter space. We report on new searches on light Higgs and light dark matter at BABAR using the 516 1/fb of data collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory.
In the Standard Model \CP violation in charm decays is expected to be very small, at the level of 0.1% or less. A significant excess of \CP violation with respect to the Standard Model predictions would be a signature of new physics. We report on recent searches for \CP violation in charm meson decays at \babar, using a data sample corresponding to an integrated luminosity of about 470 \invfb. In particular, we report on searches for \CPV in the 3-body $\Dp\to\Kp\Km\pip$ decay and for decay modes with a \KS in the final state, such as $\Dp\to\KS\Kp$, $\Ds\to\KS\Kp$, $\Ds\to\KS\pip$. A lifetime…
Recently, several charmonium-like states above $D\bar{D}$ threshold have been discovered at the BELLE and BABAR $B$-factories. Some of these states are produced via Initial State Radiation ({\it e.g.} Y(4260) and Y(4350)) and some are observed in $B$ meson decays ({\it{e.g.}} X(3872), Y(3940)). The BELLE observation of the enhancement in the $ψ(2S)π^-$, {\it {i.e.}} the $Z(4430)^-$ state, has generated a great deal of interest, because such a state must have minimum quark content ($c\bar{c}d\bar{u}$), so that it would represent the unequivocal manifestation of a four-quark meson state. Here we…
This review briefly describes light dark matter searches performed by the BABAR experiment. Although dark matter candidates have traditionally been associated with heavy particles appearing in extensions of the Standard Model, a lighter component remains a well motivated alternative, and many scenarios of light dark matter have been recently proposed. Thanks to their large luminosities, B factories offer an ideal environment to probe these possibilities, complementing searches from direct detection and satellite experiments.
Three searches for rare decays of the charmed $D^0$ meson are presented: a search for $D^0 \to \ell^+\ell^-$ published by the BaBar collaboration using about 468 fb$^{-1}$ of data and two searches for $D^0 \to γγ$, one published by the BaBar collaboration using about 470 fb$^{-1}$ of data, and a second one presented as a preliminary result by the BESIII collaboration using approximately 2.9 fb$^{-1}$. No statistically significant signal has been found, in agreement with the Standard Model predictions.
The BABAR Collaboration has performed three searches for a light Higgs boson, $A^0$, in radiative Upsilon ($Υ$) decays: $Υ(3S)\toγA^0$, $A^0\toτ^+τ^-$; $Υ(nS)\toγA^0$, $A^0\toμ^+μ^-$ ($n=2,3$); and $Υ(3S)\toγA^0$, $A^0\to$ invisible. Such a Higgs boson ($A^0$) appears in the Next-to-Minimal Supersymmetric extensions of the Standard Model, where a light CP-odd Higgs boson couples strongly to $b$-quarks. The searches are based on data samples that consist of $122\times 10^6$ $Υ(3S)$ and $99\times 10^6$ $Υ(2S)$ decays, collected by the BABAR detector at the SLAC National Accelerator Laboratory. T…
We study the $Υ(1S)$ radiative decays to $γπ^+ π^-$ and $γK^+ K^-$ using data recorded with the BaBar detector operating at the SLAC PEP-II asymmetric-energy $e^+e^-$ collider at center-of-mass energies at the $Υ(2S)$ and $Υ(3S)$ resonances. The $Υ(1S)$ resonance is reconstructed from the decay $Υ(nS)\to π^+ π^- Υ(1S)$, $n=2,3$. We also study the processes $γγ\to η_c \to η^{\prime}K^+K^-$, $η^{\prime}π^+π^-$, and $ηπ^+ π^-$ using a data sample of 519 $fb^{-1}$ recorded with the BaBar detector at center-of-mass energies at and near the $Υ(nS)$ ($n = 2,3,4$) resonances. A Dalitz plot analysis is…
A summary of the results of several recent studies of charm mixing is presented. A number of different methods were used, including the measurement of lifetime ratios for final states of different CP, time dependence of wrong-sign hadronic decays, fits to time-dependent Dalitz plots, and searches for wrong-sign semi-leptonic decays. Taken together, they suggest mixing is of order 1%. The status of searches for indirect CP violation is also reported.
We present results of searches for lepton-number and baryon-number violation in B decays using the full BaBar dataset of 471 million BBbar pairs.
We present recent results from the BaBar collaboration in several areas of research. These include searches for new physics via measurements of radiative-penguin B decays, lepton-number and lepton-flavor violations in B decays, and CP violation in tau lepton decays.
We present recent results on leptonic B decays using data collected by the BaBar detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. We report searches for the B -> tau nu decay, based on two statistically independent data samples.
We present some recent measurements performed using 514 fb-1 of $e^+e^-$ collisions collected with the BaBar detector at the PEP-II asymmetric collider at SLAC. First we present a study of the decay tau -> K K_S nu, we measure the branching fraction B(tau -> K K_S nu), the mass spectrum of the K K_S system and obtain the spectral function. Our results are in agreement with and improve previous measurements. We then report a search for a dark boson A' produced in the reaction e+e- -> gamma A' in invisible final states A' -> chi anti-chi . We find no evidence for such processes and set 90% confi…
Searches for lepton flavor violating tau -> l gamma, tau -> lll and tau -> lhh decays at the BaBar experiment are presented. Upper limits on the branching ratios are obtained at the level of 10^{-7} at 90% confidence level.
The BABAR detector at SLAC's PEP-II storage ring has collected data equivalent to about 30.4 fb-1 through June 2001. Results on CP violation, and in particular searches for direct CP violation, and measurement of rare B decays are presented.
Recent results on the search for pentaquarks and on charmonium spectroscopy at BaBar are reviewed. The latter includes the observation of the puzzling new state X(3872) -> J/psi pi+ pi- in B decays, and the searches for X(3872) in two-body B decays and initial state radiation events.
We present recent results from the \babar Collaboration on radiative decays. These include searches for new physics via measurements of several observables such as the time-dependent $CP$ asymmetry in $B^0 \to K^0_S π^- π^+ γ$ exclusive decays, as well as direct $CP$ asymmetries and branching fractions in $B \to X_s γ$ and $B \to X_s \ell^+ \ell^-$ inclusive decays.
Several types of new-physics models predict the existence of light dark matter candidates and low-mass Higgs states. Previous \babar searches for invisible light-Higgs decays have excluded large regions of model parameter space. We present searches for a dark-sector Higgs produced in association with a dark gauge boson and searches for a light Higgs in $Υ(nS)$ decays.
We present recent results concerning the searches for light Higgs-like particles in the decay $Υ(3S) \to γA^{0}, A^{0}\to μ^{+}μ^{-}$ as well as for the lepton flavour violation in the decays $Υ(3S) \to e^{\pm}τ^{\mp},μ^{\pm}τ^{\mp}$ and $τ\to 3l (l=e,μ)$ with the BaBar experiment.
The BaBar collaboration has accumulated over 400 million tau-pairs which can be used to study charged leptonic and hadronic weak currents to unprecedented precision. This note presents results on lepton universality, measurements of |V_us|, and searches for tau decays which violate lepton flavour conservation, or tau decays that proceed through a suppressed second class current.
We review recent results of the BABAR and BELLE Collaborations on the the alpha and gamma angles of the unitary triangle, on the B to K pi pi Dalitz-plot analyses, and on the searches for baryonic B decays and for B to DD decays.
We present selected new results on leptonic B meson decays from the BaBar experiment: searches for the decays B0->l+l-, B+->l+nu and B0->l+tau-, and B->Knunubar, where l=e or mu. The decay modes imply also their charge conjugations. We observe no evidence for these decays and set upper limits on their branching fractions.
I report on recent studies of hadronic physics performed by the BaBar Collaboration. Emphasis is given to the measurement of the properties of newly discovered charmed hadrons and to the searches for light and heavy pentaquarks.
We present the recent BaBar searches for the leptonic decay B+ --> tau+ nu and for the rare decay B --> K(*) nu nubar, using a data sample of about 470 x 10^6 BB pairs. Both searches use a technique in which one B meson is hadronically reconstructed before searching for evidence of the signal decay in the rest of the event. BaBar measures B(B+ --> tau+ nu) = (1.83 ^{+0.53}_{-0.49} +/- 0.24) x 10^{-4}, and preliminary upper limits at 90% confidence level of B(B --> K nu nubar) < 3.2 x 10^{-5} and B(B --> K* nu nubar) < 7.9 x 10^{-5}. We also discuss the expected observations and precision impro…
Rare B decays permit stringent tests of the Standard Model and allow searches for new physics. Several rare radiative-decay studies of the B meson from the BaBar collaboration are described. So far no sign for new physics was discovered.
We present the most recent searches for lepton-flavor-violating tau decays in BaBar. We find no evidence of tau decaying to three charged leptons or to a charged lepton and a neutral meson (KS, rho, phi, K*0, anti-K*0), and set upper limits on the corresponding branching fractions between 1.8 and 19 times 10-8 at 90% confidence level.
We present new results on hadronic B and D decays from the BABAR experiment. The first part of this document presents searches for new channels which may be used for CP measurements. The second part is dedicated to hadronic decays with tests of QCD factorization predictions and other models for B structure and decay mechanisms. A new result on the reference branching ratio Ds+ -->phi pi+ is also reported.
We review recent results from the BABAR and Belle experiments on rare electroweak B-meson decays, with emphasis on those occurring through flavor changing neutral current interactions of the type b -> s l l. The recent results include measurements of the isospin asymmetry and lepton forward-backward asymmetry in B -> K* l+ l- decays from BABAR, a search for B -> pi l+ l- from Belle, and searches for B \to K(*) nu anti-nu from BABAR. We also briefly review the status of B0 -> l+ l- and B+ -> l+ nu searches.
Model-independent techniques for CP violation searches in multi-body charm decays are discussed. Examples of recent analyses from BaBar and LHCb are used to illustrate the experimental challenges involved.
Electro-weak penguin and leptonic decays provide an indirect probe for physics beyond the Standard Model and contribute to the determination of Standard Model parameters. Copious quantities of B mesons produced at the B-Factories permit precision measurements of the electro-weak penguin decays and searches for leptonic decays. We review the current experimental status of b -> s(d) gamma, B^0 -> D^{*0} gamma, b -> s l^+ l^- and finally B->tau nu decays at BaBar.
We search for CP violation in a sample of 4.7x10^4 Cabibbo suppressed D0 -> K+K-pi+pi- decays. We use 470 fb-1 of data recorded by the BaBar detector at the PeP2 asymmetric-energy e+e- storage rings running at center-of-mass energies near 10.6 GeV. CP violation is searched for in the difference between the T-odd asymmetries, obtained using triple product correlations, measured for D0 and D0b decays. The measured At violation parameter is At = (1.0 +- 5.1_sta +- 4.4_sys) x 10^-3.
In this proceeding, results of searches for CP violation in charm decays using the full BABAR dataset are discussed. The parameter $A_{CP}$ in the decay $D^\pm\to\KSπ^\pm$ is determined to be $(-0.39 \pm 0.13 \pm 0.10)%$. Meaurements of CP violation using \T-odd correlations in the four-body decays D^+->K^+K_S^0π^+π^- and D^+_s->K^+K_S^0π^+π^- are $(-12.0 \pm 10.0_{\stat} \pm 4.6_{\syst}) \times 10^{-3}$ and $(-13.6 \pm 7.7_{\stat} \pm 3.4_{\syst}) \times10^{-3}$, respectively.
We present several searches for charmless hadronic two-body and three-body decays of B mesons from electron-positron annihilation data collected by the BABAR detector near the Upsilon(4S) resonance. We report the preliminary branching fractions BR(B0 --> pi+pi-) = (4.1 +/- 1.0 +/- 0.7) x 10^-6, BR(B0 --> K+pi-) = (16.7 +/- 1.6 +/- 1.3) x 10^-6, BR(B0 --> rho-/+ pi+/-) = (49 +/- 13 +6 -5) x 10^-6, BR(B+ --> eta' K+) = (62 +/- 18 +/- 8) x 10^-6, and present upper limits for nine other decays.
We present the results of searches for rare B meson decays. The measurements use all or part of a data sample of about 88 million $Υ(4S)\to B{\bar B}$ decays collected between 1999 and 2002 with the \babar detector at the PEP-II asymmetric energy B Factory at the Stanford Linear Accelerator Center. We study a variety of decays dominated by electromagnetic, electroweak and gluonic penguin transitions, and report measurements of branching fractions and other quantities of interest.
We present recent results of B and charm decays from the BaBar experiment. These results include searches for rare or forbidden charm decays, measurements of $|V_{ub}|$ from inclusive ${\bar B} \rightarrow X_u l {\bar ν} $ decays, observation of the semileptonic ${\bar B} \rightarrow D^{(*)} τ^- {\bar ν}_τ$ decays, direct CP violation asymmetry in $B \rightarrow X_{s+d} γ$ and in $D^+\rightarrow K^0_S π^+$, and T-violation in $D^+_{(s)} \rightarrow K^+ K^0_S π^+ π^-$. These studies are based on the final dataset collected by BaBar at the PEP-II B factory at SLAC in the period 1999-2008.
In this proceedings we present a measurement of mixing, and searches for direct and indirect CP asymmetries in the charm sector using the full \babar data sample of $469 \invfb$. Searches for direct CP asymmetries have been performed in the $D^{\pm} \to K^0_{\scriptscriptstyle S} K^\pm$, $D_s^{\pm} \to K^0_{\scriptscriptstyle S} K^\pm$, $D_s^{\pm}\to K^0_{\scriptscriptstyle S} π^\pm$, and $D^{\pm} \to K^+ K^- π^\pm$ decay channels, with both model-dependent and model-independent approaches being exploited for the last mode. The mixing measurement and the search for indirect CP asymmetry have b…
We report searches for a new muonic dark force mediated by a gauge boson ($Z'$) coupling only to the second and third lepton families. The existence of the $Z'$ boson is probed in $e^+e^- \to μ^+μ^- Z'$, $Z' \to μ^+ μ^-$ events, with an analysis based on the full data sample collected with the BABAR detector at the PEP-II $e^+e^-$ collider. No significant signal is observed. Limits on dark-sector coupling constants are derived; these improve upon current bounds, and further constrain the allowed parameter space.
We present studies in bottomonium spectroscopy carried out with samples of $(98\pm1)$ million $Υ(2S)$ and $(121\pm1)$ million $Υ(3S)$ events recorded with the BaBar detector at the PEP-II asymmetric-energy $e^+ e^-$ collider at SLAC. Precise measurements of the branching fractions for $χ_{b1,2}(1P, 2P)\rightarrow γΥ(1S)$ and $χ_{b1,2}(2P)\rightarrow γΥ(2S)$ transitions, and searches for radiative decay to the $η_b(1S)$ and $η_b(2S)$ states are performed using photons that have converted into an $e^+ e^-$ pair. In addition, we summarize the results of a search for the spin-singlet partner of th…
The $B$-factories provide rich opportunities to search for new phenomena, in $B$, charm, and tau decays. Presented here is a selection of recent results from Belle and Babar.
The results of searches for the strange pentaquark states, Theta(1540)+, Xi(1860)-- and Xi(1860)0 in data recorded by the BABAR experiment are presented. We search for these three states inclusively in 123.4 fb^-1 of e+ e- annihilation data produced at the PEP-II asymmetric storage rings; we find no evidence for their production in any physics process, and set limits on their production rates that are well below the measured rates for conventional baryons. We also search for Theta(1540)+ produced in interactions of electrons or hadrons in the material of the inner part of the detector. No evid…
I discuss the results on $D^{0}$-$\bar{D}^{0}$ mixing through hadronic as well as semi-leptonic charm decays, rare flavor-changing neutral currents in the charm sector and the lepton flavor violating $τ$ decaying to charged lighter leptons. The results from both BABAR and Belle are presented in this review.
This article gives an overview of the recent searches and measurements of $b\to d$ penguin transitions with the BaBar experiment. The branching fraction of these decays in the Standard Model (SM) is expected to be a factor of 10 or more lower than the corresponding $b\to s$ penguin transitions, but a deviation from the SM prediction would be an equally striking sign of new physics. The exclusive decay $B\toπ\ell\ell$ is searched by BaBar with no excess over the background found. The BaBar measurement of $B\to(ρ,ω)γ$ provides the first evidence of $B^+\toρ^+γ$, is in good agreement with the pre…
Radiative and electroweak decays of B mesong (B to X_{s(d)}γ and B to X_{s(d)}\ell\ell, respectively, where X is a hadronic system and s or d labels the underlying quark process b to s(d)γ) provide good places to search for new physics (NP) beyond the standard model. Recent BaBar measurements are reported: inclusive BF(B to X_s γ), direct CP asymmetry for inclusive X_s γ and X_{s+d} γ, and searches for the rare decays B to π(η)\ell\ell. No evidence for NP was found, but several constraints are discussed.
We report an update to our previous measurement of the CKM element $|V_{ub}|$ using exclusive $B \rightarrow π\ell ν$ decays. In the charm sector we have performed a measurement of $f_{Ds}$ using $D_s\rightarrowτ^+ν_τ$ decays, we have measured the mixing parameter $y_{CP}$ using the lifetime ratio $\frac{\langleτ_{Kπ}\rangle}{\langleτ_{hh}\rangle}$ in $D^0$ decays, and we have also searched for CP violation using T-odd correlations in $D^0$ decays to $K^+K^-π^+π^-$. Finally, in the tau sector we have performed a search for the lepton flavor violating decays $τ^\pm \rightarrow e^\pm γ$ and $τ^\…
Large production of the $\ccbar$ pairs and high integrated luminosity make the PEPII B-Factory, an excellent place for studying the charm hadrons. In this paper, we present a few of the most recent results from the BaBar collaboration in the charm sector.
Recent results on the search for new physics at BaBar and Belle B-factories are presented. The search for a light Higgs boson produced in the decay of different Y resonances is shown. In addition, recent measurements aimed to discover invisible final states produced by new physics mechanisms beyond the standard model are presented.
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 present a review of recent results from BaBar experiment. BaBar detector has collected about 256 millions of $B\bar B$ events at PEP-II, the asymmetric $e^+e^-$ collider located at SLAC running at the $Υ(4S)$ resonance. We have studied CP violation in B mesons, observing the first evidence of direct CP violation in B meson decays and measured CP asymmetries relevant for the determination of the angles of the CKM Unitarity Triangle. BaBar physics program covers many other topics, including measurements of CKM matrix elements, charm physics, and search for new physics processes.
The BaBar experiment and the PEP-II accelerator at SLAC started to take data on May 26, 1999. By the time of this conference, the recorded integrated luminosity was 20 fb^{-1}, of which 8 fb^{-1} were analyzed to provide a first set of physics results. This talk reviews the first measurement of sin2beta and the study of B meson decays to charmonium modes and 2-body charmless decays.
The BABAR experiment has been taking data since about one year. Physics results, complementary to those described by G.Sciolla elsewhere in these Proceedings, are presented: various measurements of the neutral and charged B mesons lifetimes, the B^0 mixing frequency, the mistag fractions, and the B --> D_s^(*) X and B^0 --> D_s^(*)+ D^* branching ratios. Some prospects for the close future are shown. All the numbers given here are preliminary.
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