Search results for "BABAR experiment"
showing 10 items of 42 documents
Search for a Stable Six-Quark State at BABAR
2019
Recent investigations have suggested that the six-quark combination uuddss could be a deeply bound state (S) that has eluded detection so far, and a potential dark matter candidate. We report the first search for a stable, doubly strange six-quark state in Upsilon -> S anti-Lambda anti-Lambda decays based on a sample of 90 million Upsilon(2S) and 110 million Upsilon(3S) decays collected by the BABAR experiment. No signal is observed, and 90% confidence level limits on the combined Upsilon(2S,3S) -> S anti-Lambda anti-Lambda branching fraction in the range (1.2-1.4)x10^-7 are derived for m_S < 2.05 GeV. These bounds set stringent limits on the existence of such exotic particles.
BaBar Results on Hadronic Cross Sections with Initial State Radiation
2008
In this paper we present recent results of the BaBar experiment at the B-factory PEP-II in the field of hadronic cross section measurements. At PEP-II, which is designed for a fixed center-of-mass energy around the ϒ(4S) resonance, the hadronic cross section is measured using events with Initial State Radiation (ISR), which allows the cover the entire energy range below 4 GeV in one single experiments. Results for exclusive finals states with 3, 4 and 5 hadrons, as well as measurements of hyperon form factors are shown.
Search for a Dark Leptophilic Scalar in e(+) e(-) Collisions
2020
Many scenarios of physics beyond the standard model predict the existence of new gauge singlets, which might be substantially lighter than the weak scale. The experimental constraints on additional scalars with masses in the MeV to GeV range could be significantly weakened if they interact predominantly with leptons rather than quarks. At an e+e- collider, such a leptophilic scalar (φL) would be produced predominantly through radiation from a τ lepton. We report herein a search for e+e-→τ+τ-φL, φL→ℓ+ℓ- (ℓ=e, μ) using data collected by the BABAR experiment at SLAC. No significant signal is observed, and we set limits on the φL coupling to leptons in the range 0.04<mφL<7.0 GeV. These bounds s…
Search ForT,CP, andCPTViolation inB0−B¯0Mixing with Inclusive Dilepton Events
2006
The authors report the results of a search for T, CP and CPT violation in B{sup 0}-{bar B}{sup 0} mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II B Factory. Using a sample of 232 million B{bar B} pairs, with a simultaneous likelihood fit of the same-sign and opposite-sign dileptons, they measure the T and Cp violation parameter |q/p|-1 = (-0.8 {+-} 2.7(stat.) {+-} 1.9(syst.)) x 10{sup -3}, and the CPT and CP parameters Im z = (-13.9 {+-} 7.3(stat.) {+-} 3.2(syst.)) x 10{sup -3} and {Delta}{Lambda} x Re z = (-7.1 {+-} 3.9(stat.) {+-} 2.0(syst.)) x 10{sup -3} ps{sup -1}. The statistical correlation between the measurements of Im z and {Delta}{Lambda} …
Exclusive initial-state-radiation production of theDD¯,D*D¯, andD*D¯*systems
2009
We perform a study of the exclusive production of in initial-state-radiation events, from e(+)e(-) annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium and possible new resonances. The data sample corresponds to an integrated luminosity of 384 fb(-1) and was recorded by the BABAR experiment at the PEP-II storage rings. The D (D) over bar, D*(D) over bar, D*(D) over bar* mass spectra show clear evidence of several psi resonances. However, there is no evidence for Y(4260) -> D*(D) over bar or Y(4260) -> D*(D) over bar*.
Study of theDsJ*(2317)+andDsJ(2460)+mesons in inclusivecc¯production nears=10.6 GeV
2006
A study of the $D_{sJ}^*(2317)^+$ and $D_{sJ}(2460)^+$ mesons in inclusive $c\bar{c}$ production is presented using 232~${\rm fb}^{-1}$ of data collected by the BaBar experiment near $\sqrt{s} = 10.6$~\gev. Final states consisting of a $D_s^+$ meson along with one or more $\pi^0$, $\pi^\pm$, or $\gamma$ particles are considered. Estimates of the mass and limits on the width are provided for both mesons and for the $D_{s1}(2536)^+$ meson. A search is also performed for neutral and doubly-charged partners of the $D_{sJ}^*(2317)^+$ meson.
Measurement ofCPasymmetries and branching fractions in charmless two-bodyB-meson decays to pions and kaons
2013
We present improved measurements of CP-violation parameters in the decays B^0→π^+π^-, B^0→K^+π^-, and B^0→π^0π^0, and of the branching fractions for B^0→π^0π^0 and B^0→K^0π^0. The results are obtained with the full data set collected at the Υ(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, corresponding to (467±5)×10^6 BB pairs. We find the CP-violation parameter values and branching fractions: S_(π^+π^-)=-0.68±0.10±0.03, C_(π^+π^-)=-0.25±0.08±0.02, A_(K^-π^+)=-0.107±0.016_(-0.004)^(+0.006), C_(π^0π^0)=-0.43±0.26±0.05, B(B^0→π^0π^0)=(1.83±0.21±0.13)×10^(-6), B(B^0→K^0π^0)= (10.1±0.6±0.4)×10^(-6), where in each cas…
Tests ofCPTsymmetry inB0−B¯0mixing and inB0→cc¯K0decays
2016
Using the eight time dependences for the decays Upsilon(4S)-> B0 B0bar -> fj fk with the dacay into a flavor-specific state fj = ell+- X before or after the decay into a CP eigenstate fk = c cbar KS,KL, as measured by the BABAR experiment, we determine the three CPT-sensitive parameters Re(z) and Im(z) in B0-B0bar mixing and |Abar/A| in B0 -> c cbar K0 decays. We find Im(z) = 0.010 +- 0.030 +- 0.013, Re(z) = -0.065 +- 0.028 +- 0.014, and |Abar/A| = 0.999 +- 0.023 +- 0.017, in agreement with CPT symmetry.
Improved limits onB0decays to invisible(+γ)final states
2012
We establish improved upper limits on branching fractions for B-0 decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance by the BABAR experiment at the PEP-II e(+)e(-) storage ring at the SLAC National Accelerator Laboratory, we establish upper limits at the 90% confide…
Measurement ofB(B→Xsγ), theB→Xsγphoton energy spectrum, and the directCPasymmetry inB→Xs+dγdecays
2012
The photon spectrum in B → X_sγ decay, where X_s is any strange hadronic state, is studied using a data sample of (382.8±4.2) × 10^6 e^+e^- → Υ(4S) → BB events collected by the BABAR experiment at the PEP-II collider. The spectrum is used to measure the branching fraction B(B → X_sγ)=(3.21±0.15±0.29±0.08) × 10^(-4) and the first, second, and third moments ⟨E_γ⟩=2.267±0.019±0.032±0.003 GeV, ⟨(E_γ-⟨E_γ⟩)^2⟩=0.0484±0.0053±0.0077±0.0005 GeV^2, and ⟨(E_γ-⟨E_γ⟩)^3⟩=-0.0048±0.0011±0.0011±0.0004 GeV^3, for the range E_γ > 1.8 GeV, where E_γ is the photon energy in the B-meson rest frame. Results are also presented for narrower E_γ ranges. In addition, the direct CP asymmetry A_(CP)(B → X_(s+d)γ…