|
|
Campanario, F., Roth, R., & Zeppenfeld, D. (2015). QCD radiation in WH and WZ production and anomalous coupling measurements. Phys. Rev. D, 91(5), 054039–10pp.
Abstract: We study QCD radiation for the WH and WZ production processes at the LHC. We identify the regions sensitive to anomalous couplings, by considering jet observables, computed at next-to-leading-order QCD with the use of the Monte Carlo program VBFNLO. Based on these observations, we propose the use of a dynamical jet veto. The dynamical jet veto avoids the problem of large logarithms depending on the veto scale, hence providing more reliable predictions and simultaneously increasing the sensitivity to anomalous coupling searches, especially in the WZ production process.
|
|
|
|
BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2015). Measurement of the D-0 -> pi(-)e(+)nu(e) differential decay branching fraction as a function of q(2) and study of form factor parametrizations. Phys. Rev. D, 91(5), 052022–25pp.
Abstract: Based on a sample of 500 million e(+)e(-) -> c (c) over bar events recorded by the BABAR detector at c. m. energies of close to 10.6 GeV, we report on a study of the decay D0 ->pi(-)e(+)nu(e). We measure the ratio of branching fractions, R-D = B(D-0 -> pi(-)e(+)nu(e))/beta(D-0 -> K-pi(+)) = 0.0713 +/- 0.0017(stat) +/- 0.0024(syst), and use the present world average for B(D-0 -> K-pi(+)) to obtain B(D-0 -> pi(-)e(+)nu e) = (2.770 +/- 0.068(stat) +/- 0.092(syst) +/- 0.037(ext)) x 10(-3) where the third error accounts for the uncertainty on the branching fraction for the reference channel. The measured dependence of the differential branching fraction on q(2), the four-momentum transfer squared between the D and the pi meson, is compared to various theoretical predictions for the hadronic form factor, f(+,D)(pi)(q(2)), and the normalization vertical bar V-cd vertical bar x f(+,D)(pi)(q(2) = 0) = 0.1374 +/- 0.0038(stat) +/- 0.0022(sys)t +/- 0.0009(ext). is extracted from a fit to data. Using the most recent LQCD prediction of f(+,D)(pi)(q(2) = 0) = 0.666 +/- 0.029, we obtain vertical bar V-cd vertical bar = 0.206 +/- 0.007(exp) +/- 0.009(LQCD). Assuming, instead, vertical bar V-cd vertical bar = vertical bar V-us vertical bar = 0.2252 +/- 0.0009, we obtain f(+,D)(pi)(q(2) = 0) = 0.610 +/- 0.020(exp) +/- 0.005(ext). The q(2) dependence of f(+,D)(pi)(q(2)) is compared to a variety of multipole parametrizations. This information is applied to B-0 -> pi(-)e(+)nu(e) decays and, combined with an earlier B-0 -> pi(-)e(+)nu(e) measurement by BABAR, is used to derive estimates of vertical bar V-ub vertical bar.
|
|
|
|
BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2015). Measurement of the branching fractions of the radiative leptonic tau decays tau -> e gamma v(v)over-bar and tau -> μgamma v(v)over-bar at BABAR. Phys. Rev. D, 91(5), 051103–8pp.
Abstract: We perform a measurement of the tau -> l gamma v (v) over bar (l = e, mu) branching fractions for a minimum photon energy of 10 MeV in the tau rest frame, using 431 fb(-1) of e(+) e(-) collisions collected at the center-of-mass energy of the Upsilon(4S) resonance with the BABAR detector at the PEP-II storage rings. We find B(tau -> μgamma v (v) over bar = (3.69 +/- 0.03 +/- 0.10) x 10(-3) and B(tau -> e gamma v (v) over bar = (1.847 +/- 0.015 +/- 0.052) x 10(-2), where the first quoted error is statistical and the second is systematic. These results are substantially more precise than previous measurements.
|
|
|
|
Dias, J. M., Aceti, F., & Oset, E. (2015). Study of B<(B)over bar>* and B*<(B)over bar>* interactions in I=1 and relationship to the Z(b)(10610), Z(b)(10650) states. Phys. Rev. D, 91(7), 076001–14pp.
Abstract: We use the local hidden gauge approach in order to study the B (B) over bar* and B*(B) over bar* interactions for isospin I = 1. We show that both interactions via one light meson exchange are not allowed by the Okubo-ZweigIizuka rule and, for that reason, we calculate the contributions due to the exchange of two pions, interacting and noninteracting among themselves, and also due to the heavy vector mesons. Then, to compare all these contributions, we use the potential related to the heavy vector exchange as an effective potential corrected by a factor which takes into account the contribution of the other light meson exchanges. In order to look for poles, this effective potential is used as the kernel of the Bethe-Salpeter equation. As a result, for the B (B) over bar* interaction we find a loosely bound state with mass in the range 10587-10601 MeV, very close to the experimental value of the Z(b)(10610) reported by the Belle Collaboration. For the B*(B) over bar* case, we find a cusp at 10650 MeV for all spin J = 0, 1, 2 cases.
|
|
|
|
BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2015). Search for a light Higgs resonance in radiative decays of the Upsilon(1S) with a charm tag. Phys. Rev. D, 91(7), 071102–9pp.
Abstract: A search is presented for the decay Upsilon(1S) -> gamma A(0), A(0) -> c (c) over barc, where A(0) is a candidate for the CP-odd Higgs boson of the next-to-minimal supersymmetric standard model. The search is based on data collected with the BABAR detector at the Upsilon(2S) resonance. A sample of Upsilon(1S) mesons is selected via the decay Upsilon(2S) -> pi(+)pi(-)Upsilon(1S) . The A(0) -> c (c) over bar decay is identified through the reconstruction of hadronic D-0, D+,and D-0 (2010)(+) meson decays. No significant signal is observed. The measured 90% confidence-level upper limits on the product branching fraction beta(Upsilon(1S) -> gamma A(0)) x beta(A(0) -> (c) over barc range from 7.4 x 10(-5) to 2.4 x 10(-3) for A(0) masses from 4.00 to 8.95 GeV/c(2) and 9.10 to 9.25 GeV/c(2), where the region between 8.95 and 9.10 GeV/c(2) is excluded because of background from Upsilon(2S) -> gamma chi(bJ)(1P), chi(bJ)(1P) -> gamma Upsilon(1S) decays.
|
|
