A search for charmed baryons decaying to D(0)p reveals two states: the Lambdac(2880)+ baryon and a previously unobserved state at a mass of 2939.8+/-1.3(stat)+/-1.0(syst) MeV/c2 and with an intrinsic ...width of 17.5+/-5.2(stat)+/-5.9(syst) MeV. Consistent and significant signals are observed for the K(-)pi(+) and K(-)pi(+)pi(-)pi(+) decay modes of the D0 in 287 fb(-1) annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D+p spectrum of doubly charged partners. The mass and intrinsic width of the Lambdac(2880)+ baryon and relative yield of the two baryons are also measured.
We present improved measurements of the branching fraction B , the longitudinal polarization fraction f L , and the direct C P asymmetry A C P in the B meson decay channel B + → ρ + ρ 0 . The data ...sample was collected with the BABAR detector at SLAC. The results are B ( B + → ρ + ρ 0 ) = ( 23.7 ± 1.4 ± 1.4 ) × 10 − 6 , f L = 0.950 ± 0.015 ± 0.006 , and A C P = − 0.054 ± 0.055 ± 0.010 , where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the Cabibbo-Kobayashi-Maskawa phase angle α = arg ( − V t d V ∗ t b / V u d V ∗ u b ) to be ( 92.4 + 6.0 − 6.5 ) ° .
We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K ± π ∓ π ± . Using a sample of ( 383.2 ± 4.2 ) × 10 6 B ¯¯¯ B pairs collected by the BABAR ...detector, we measure C P -averaged branching fractions and direct C P asymmetries for intermediate resonant and nonresonant contributions. We find evidence for direct C P violation in the decay B ± → ρ 0 ( 770 ) K ± , with a C P -violation parameter A C P = ( + 44 ± 10 ± 4 + 5 − 13 ) % .
We measure the direct CP violation asymmetry, A_CP, in B to X_s gamma and the isospin difference of the asymmetry, Delta A_CP, using 429 fb^-1 of data collected at Upsilon(4S) resonance with the ...BaBar detector at the PEP-II asymmetric-energy e+e- storage rings operating at the SLAC National Accelerator Laboratory. B mesons are reconstructed from 10 charged B final states and 6 neutral B final states. We find A_CP = +(1.7 +- 1.9 +- 1.0)%, which is in agreement with the Standard Model prediction and provides an improvement on the world average. Moreover, we report the first measurement of the difference between A_CP for charged and neutral decay modes, Delta A_CP = +(5.0 +- 3.9 +- 1.5)%. Using the value of Delta A_CP, we also provide 68% and 90% confidence intervals on the imaginary part of the ratio of the Wilson coefficients corresponding to the chromo-magnetic dipole and the electromagnetic dipole transitions.
We report results from an updated study of the suppressed decays B- to D K- and B- to D* K- followed by D to K+pi-, where D(*) indicates a D(*)0 or an anti-D(*)0 meson, and D* decays to D pi0 or D ...gamma. These decays are sensitive to the CKM unitarity triangle angle gamma, due to interference between the b to c transition B- to D(*)0K- followed by the doubly Cabibbo-suppressed decay D0 to K+pi-, and the b to u transition B- to anti-D(*)0K- followed by the Cabibbo-favored decay anti-D0 to K+pi-. We also report an analysis of the decay B- to D(*)pi- with the D decaying into the doubly Cabibbo-suppressed mode D to K+pi-. Our results are based on 467 million Upsilon (4S) to B anti-B decays collected with the BaBar detector at SLAC. We measure the ratios R(*) of the suppressed (K+pi-_D K-/pi-) to favored (K-pi+_D K-/pi-) branching fractions as well as the CP asymmetries A(*) of those modes. We see indications of signals for the B- to D K- and B- to D*K-, D*->D pi0 suppressed modes, with statistical significances of 2.1 and 2.2 sigma, respectively, and we measure: R_{DK} = (1.1\pm 0.6 \pm 0.2)\times 10^{-2}, A_{DK} = -0.86 \pm 0.47 \ ^{+0.12}_{-0.16}, R*_{(D pi0)K} = (1.8\pm 0.9 \pm 0.4)\times 10^{-2}, A*_{(D pi0)K} = +0.77 \pm 0.35\pm 0.12, R*_{(D gamma)K} = (1.3\pm 1.4\pm 0.8 )\times 10^{-2}, A*_{(D gamma)K} = +0.36 \pm 0.94\ ^{+0.25}_{-0.41}, where the first uncertainty is statistical and the second is systematic. We use a frequentist approach to obtain the magnitude of the ratio r_B = |A(B- to anti-D0 K-) / A(B- to D0K-)|= (9.5^{+5.1}_{-4.1})%, with r_B<16.7% at 90% confidence level. In the case of B- to D* K- we find r*_B = |A(B^- to anti-D*0 K-)/A(B- to D*0 K-)|=(9.6^{+3.5}_{-5.1})%, with r*_B<15.0% at 90% confidence level.
We report the observation of charmless hadronic decays of charged B mesons to the final state K{+}K{-}pi{+}. Using a data sample of 347.5 fb{-1} collected at the Upsilon(4S) resonance with the BABAR ...detector, we observe 429+/-43 signal events with a significance of 9.6sigma. We measure the inclusive branching fraction B(B{+}-->K{+}K{-}pi{+})=5.0+/-0.5(stat)+/-0.5(syst)x10{-6}. Inspection of the Dalitz plot of signal candidates shows a broad structure peaking near 1.5 GeV/c{2} in the K+K- invariant mass distribution. We find the direct CP asymmetry to be consistent with zero.
Search for the Z ( 4430 ) − at BABAR Aubert, B.; Lees, J. P.; Prudent, X. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
06/2009, Letnik:
79, Številka:
11
Journal Article
Recenzirano
Odprti dostop
We report the results of a search for Z ( 4430 ) − decay to J / ψ π − or ψ ( 2 S ) π − in B − , 0 → J / ψ π − K 0 , + and B − , 0 → ψ ( 2 S ) π − K 0 , + decays. The data were collected with the ...BABAR detector at the SLAC PEP-II asymmetric-energy e + e − collider operating at center-of-mass energy 10.58 GeV, and the sample corresponds to an integrated luminosity of 413 fb − 1 . Each K π − mass distribution exhibits clear K ∗ ( 892 ) and K ∗ 2 ( 1430 ) signals, and the efficiency-corrected spectrum is well described by a superposition of the associated Breit-Wigner intensity distributions, together with an S -wave contribution obtained from the LASS I = 1 / 2 K π − scattering amplitude measurements. Each K π − angular distribution varies significantly in structure with K π − mass, and is represented in terms of low-order Legendre polynomial moments. We find that each J / ψ π − or ψ ( 2 S ) π − mass distribution is well described by the reflection of the measured K π − mass and angular distribution structures. We see no significant evidence for a Z ( 4430 ) − signal for any of the processes investigated, neither in the total J / ψ π − or ψ ( 2 S ) π − mass distribution, nor in the corresponding distributions for the regions of K π − mass for which observation of the Z ( 4430 ) − signal was reported. We obtain branching-fraction upper limits B ( B − → Z − ¯¯¯¯ K 0 , Z − → J / ψ π − ) < 1.5 × 10 − 5 , B ( B 0 → Z − K + , Z − → J / ψ π − ) < 0.4 × 10 − 5 , B ( B − → Z − ¯¯¯¯ K 0 , Z − → ψ ( 2 S ) π − ) < 4.7 × 10 − 5 , and B ( B 0 → Z − K + , Z − → ψ ( 2 S ) π − ) < 3.1 × 10 − 5 at 95% confidence level, where the Z ( 4430 ) − mass and width have been fixed to the reported central values.
We report results of a search for CPT and Lorentz violation in B(0)-Bover (0) oscillations using inclusive dilepton events from 232 x 10(6) Upsilon(4S)-->BBover decays recorded by the BABAR detector ...at the PEP-II B Factory at SLAC. We find 2.8sigma significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth's sidereal frequency and extract values for the quantities Deltaa(micro) in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 yr(-1) to 2.1 solar day(-1) are also compatible with no signal.
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