We study the process e+e−→π+π−ηγ, where the photon is radiated from the initial state. About 8000 fully reconstructed events of this process are selected from the BABAR data sample with an integrated ...luminosity of 469 fb−1. Using the π+π−η invariant mass spectrum, we measure the e+e−→π+π−η cross section in the e+e− center-of-mass energy range from 1.15 to 3.5 GeV. The cross section is well described by the Vector-Meson dominance model with four ρ-like states. We observe 49±9 events of the J/ψ decay to π+π−η and measure the product ΓJ/Ψ→e+e−BJ/Ψ→π+π−η=2.34±0.43stat±0.16syst eV.
Using the initial-state radiation method, the e + e − → KSKL cross section from 1.98 to 2.54 GeV is measured in a data sample of 469 fb −1 collected with the BABAR detector. The results are used in ...conjunction with previous BABAR results for the e + e − → K + K − , e + e − → π + π − , e + e − → π + π − η , and e + e − → ω π π cross sections to investigate the nature of the resonance structure recently observed by the BESIII experiment in the e + e − → K+K− cross section.
Track finding efficiency in B A B AR Allmendinger, T.; Bhuyan, B.; Brown, D.N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2013, Letnik:
704
Journal Article
A study of the two-body decays B±→Xcc¯K±, where Xcc¯ 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 BB+→X(3872)K+=2.1±0.6(stat)±0.3(syst)×10−4 is measured for the first time. It follows that BX(3872)→J/ψπ+π−=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance.
A search is presented for the four-body decay B0→ppp¯p¯ in a sample of 471 million BB¯ pairs collected with the BABAR detector, operated at the SLAC PEP-II asymmetric-energy e+e− collider. The ...center-of-mass energy is 10.58 GeV. From a fit to the distribution of the energy-substituted mass mES, the branching fraction B(B0→ppp¯p¯)=(1.1±0.5±0.2)×10−7 is extracted, where the first uncertainty is statistical and the second is systematic. The significance of the signal, including the systematic uncertainty, is 2.9 standard deviations. The upper limit on the branching fraction is determined to be 2.0×10−7 at 90% confidence level.
Track finding efficiency in BABAR Allmendinger, T.; Bhuyan, B.; Brown, D.N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2013, Letnik:
704
Journal Article
Recenzirano
Odprti dostop
We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BABAR detector. The first two studies measure the tracking efficiency of a charged particle ...using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of KS0 particles. The first section also examines the stability of the measurements vs. BABAR running periods.
We report measurements of sin2β and cos2β using a time-dependent Dalitz plot analysis of B0 → D ( * ) h0 with D → KS0π+π- decays, where the light unflavored and neutral hadron h0 is a π0 , η , or ω ...meson. The analysis uses a combination of the final data sets of the B a B ar and Belle experiments containing 471×106 and 772×106 B B ¯ pairs collected at the Υ ( 4S ) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. We measure sin2β=0.80±0.14 ( stat ) ±0.06 ( syst ) ±0.03 ( model ) and cos2β=0.91±0.22 ( stat ) ±0.09 ( syst ) ±0.07 ( model ) . The result for the direct measurement of the angle is β= ( 22.5±4.4 ( stat ) ±1.2 ( syst ) ±0.6 ( model ) ) ° . The last quoted uncertainties are due to the composition of the D0 → KS0π+π- decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a high-statistics e+e- → c c ¯ data sample as part of this analysis. We find the first evidence for cos2β>0 at the level of 3.7 standard deviations. The measurement excludes the trigonometric multifold solution π / 2-β= ( 68.1±0.7 ) ° at the level of 7.3 standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of β=0° is ruled out at the level of 5.1 standard deviations, and thus CP violation is observed in B0 → D ( * ) h0 decays. The measurement assumes no direct CP violation in B0 → D ( * ) h0 decays.
A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model of particle physics. In this Letter, the search for the signal of such a ...U(1) gauge boson in electron-positron pair production at the spectrometer setup of the A1 Collaboration at the Mainz Microtron is described. Exclusion limits in the mass range of 40 MeV/c^{2} to 300 MeV/c^{2}, with a sensitivity in the squared mixing parameter of as little as ε^{2}=8×10^{-7} are presented. A large fraction of the parameter space has been excluded where the discrepancy of the measured anomalous magnetic moment of the muon with theory might be explained by an additional U(1) gauge boson.
A new dark sector antibaryon, denoted ψ_{D}, could be produced in decays of B mesons. This Letter presents a search for B^{+}→ψ_{D}+p (and the charge conjugate) decays in e^{+}e^{-} annihilations at ...10.58 GeV, using data collected in the BABAR experiment. Data corresponding to an integrated luminosity of 398 fb^{-1} are analyzed. No evidence for a signal is observed. Branching fraction upper limits in the range from 10^{-7}-10^{-5} are obtained at 90% confidence level for masses of 1.0<m_{ψ_{D}}<4.3 GeV/c^{2}. The result is also reinterpreted to provide the first limits on a supersymmetric model with R-parity violation and a light neutralino.
PDF
