Initial State Radiation Physics at the B Factories

A mini-review of the recent BaBar and Belle results on the process e{sup +}e{sup -} {yields} hadrons using the initial state radiation (ISR) technique, is presented. ISR studies at the {Upsilon}(4s) resonance (B-Factories) can yield to the same observables as the low energy e{sup +}e{sup -} experiments: Precise cross-section measurements, the R ratio (ratio of cross-sections of hadron production to di-muon production) measurement, form factors measurements (from hadron pair production such as e{sup +}e{sup -} {yields} p{bar p}, {Lambda}{bar {Lambda}}, {Lambda}{bar {Sigma}}, {Sigma}{bar {Sigma}}), as well as J{sup PC} = 1{sup --} hadron spectroscopy that can lead to the discovery of new states

Search for rare or forbidden decays of the D0 meson

We present a search for nine lepton-number-violating and three lepton-flavor-violating neutral charm decays of the type D0→h'−h−ℓ'+ℓ+ and D0→h'−h+ℓ'±ℓ∓, where h and h′ represent a K or π meson and ℓ and ℓ′ an electron or muon. The analysis is based on 468 fb−1 of e+e− annihilation data collected at or close to the Υ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signal is observed for any of the twelve modes, and we establish 90% confidence level upper limits on the branching fractions in the range (1.0–30.6)×10−7. The limits are between 1 and 3 orders of magnitude more stringent than previous measurements.publishedVersio

Measurements of the absolute branching fractions of B± →k±Xc c

A study of the two-body decays B±→Xc¯cK±, where Xc¯c refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424 fb−1. The absolute determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B+→X(3872)K+ at the 3σ level. The absolute branching fraction B[B+→X(3872)K+]=[2.1±0.6(stat)±0.3(syst)]×10−4 is measured for the first time. It follows that B[X(3872)→J/ψπ+π−]=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance.publishedVersio

Light meson spectroscopy from Dalitz plot analyses of ηc decays to η0 K+K− , η0 π + π − , and ηπ + π − produced in two-photon interactions

We study the processes γγ→ηc→η′K+K−, η′π+π−, and ηπ+π− using a data sample of 519  fb−1 recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e− collider at center-of-mass energies at and near the Υ(nS) (n=2, 3, 4) resonances. This is the first observation of the decay ηc→η′K+K− and we measure the branching fraction Γ(ηc→η′K+K−)/(Γ(ηc→η′π+π−)=0.644±0.039stat±0.032sys. Significant interference is observed between γγ→ηc→ηπ+π− and the nonresonant two-photon process γγ→ηπ+π−. A Dalitz plot analysis is performed of ηc decays to η′K+K−, η′π+π−, and ηπ+π−. Combined with our previous analysis of ηc→K¯Kπ, we measure the K∗0(1430) parameters and the ratio between its η′K and πK couplings. The decay ηc→η′π+π− is dominated by the f0(2100) resonance, also observed in J/ψ radiative decays. A new a0(1700)→ηπ resonance is observed in the ηc→ηπ+π− channel. We also compare ηc decays to η and η′ final states in association with scalar mesons as they relate to the identification of the scalar glueball.publishedVersio

Pentaquark Searches at the BaBar Experiment

A review of the results in the inclusive and exclusive searches for pentaquark states obtained from the analysis of the data recorded at the BABAR experiment at the Stanford Linear Accelerator Center PEP-II B-Factory, is presented. Inclusive searches for the strange pentaquark states {Theta}{sub 5}(1540){sup +}, {Xi}{sub 5}(1860){sup --} and {Xi}{sub 5}(1860){sup 0} have been performed in a dataset of e{sup +}e{sup -} annihilations corresponding to 123.4 fb{sup -1} of integrated luminosity. No evidence is found and therefore the corresponding 95% confidence level upper limits on the {Theta}{sub 5}(1540){sup +} and {Xi}{sub 5}(1860){sup --} production rate are set. Additionally the decay {Theta}{sub 5}(1540){sup +} {yields} pK{sub S}{sup 0} has been searched for in events that correspond to interactions of both electrons and hadrons with the inner-most material of the BABAR detector, but then again, no evidence for such a process is found as a result of this analysis. The exclusive search of the {Theta}*{sup ++} pentaquark in the B meson decay B{sup +} {yields} {bar p}{Theta}*{sup ++} where {Theta}*{sup ++} {yields} pK{sup +}, has been carried out in a dataset of 210 fb{sup -1}. The results show no evidence for such a pentaquark in the mass range from 1.43 to 2.00 GeV/c{sup 2} and thus the corresponding upper limits at the 90% confidence level has been set on the product of the branching fractions (BF's) BF(B{sup +} {yields} {bar p}{Theta}*{sup ++}) x BF({Theta}*{sup ++} {yields} pK{sup +}) at the 10{sup -7} level