Showing papers by "B. G. Fulsom published in 2020"

Search for B + → μ + ν μ and B + → μ + N with inclusive tagging

Abstract: We report the result for a search for the leptonic decay of B$^{+}$ → μ$^{+}$ν$_{μ}$ using the full Belle dataset of 711 fb$^{-1}$ of integrated luminosity at the ϒ(4S) resonance. In the Standard Model leptonic B-meson decays are helicity and Cabibbo-Kobayashi-Maskawa suppressed. To maximize sensitivity an inclusive tagging approach is used to reconstruct the second B meson produced in the collision. The directional information from this second B meson is used to boost the observed μ into the signal B-meson rest frame, in which the μ has a monochromatic momentum spectrum. Though its momentum is smeared by the experimental resolution, this technique improves the analysis sensitivity considerably. Analyzing the μ momentum spectrum in this frame we find B(B$^{+}$ → μ$^{+}$ν$_{μ}$) = 5.3 ± 2.0 ± 0.9) × 10$^{-7}$ with a one-sided significance of 2.8 standard deviations over the background-only hypothesis. This translates to a frequentist upper limit of B(B$^{+}$ → μ$^{+}$ν$_{μ}$) < 8.6 × 10$^{-7}$ at 90% confidence level. The experimental spectrum is then used to search for a massive sterile neutrino, B$^{+}$ → μ$^{+}$N, but no evidence is observed for a sterile neutrino with a mass in a range of 0–1.5 GeV. The determined B$^{+}$ → μ$^{+}$ν$_{μ}$ branching fraction limit is further used to constrain the mass and coupling space of the type II and type III two-Higgs-doublet models.

Search for a Dark Leptophilic Scalar in e(+) e(-) Collisions

Abstract: Author(s): Lees, JP; Poireau, V; Tisserand, V; Grauges, E; Palano, A; Eigen, G; Brown, DN; Kolomensky, Yu G; Fritsch, M; Koch, H; Schroeder, T; Cheaib, R; Hearty, C; Mattison, TS; McKenna, JA; So, RY; Blinov, VE; Buzykaev, AR; Druzhinin, VP; Golubev, VB; Kozyrev, EA; Kravchenko, EA; Onuchin, AP; Serednyakov, SI; Skovpen, Yu I; Solodov, EP; Todyshev, K Yu; Lankford, AJ; Dey, B; Gary, JW; Long, O; Eisner, AM; Lockman, WS; Panduro Vazquez, W; Chao, DS; Cheng, CH; Echenard, B; Flood, KT; Hitlin, DG; Kim, J; Li, Y; Lin, DX; Miyashita, TS; Ongmongkolkul, P; Oyang, J; Porter, FC; Rohrken, M; Huard, Z; Meadows, BT; Pushpawela, BG; Sokoloff, MD; Sun, L; Smith, JG; Wagner, SR; Bernard, D; Verderi, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Fioravanti, E; Garzia, I; Luppi, E; Santoro, V; Calcaterra, A; de Sangro, R; Finocchiaro, G; Martellotti, S; Patteri, P; Peruzzi, IM; Piccolo, M; Rotondo, M; Zallo, A; Passaggio, S; Patrignani, C; Shuve, BJ; Lacker, HM; Bhuyan, B; Mallik, U; Chen, C; Cochran, J; Prell, S; Gritsan, AV; Arnaud, N; Davier, M | Abstract: 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 (ϕ_{L}) would be produced predominantly through radiation from a τ lepton. We report herein a search for e^{+}e^{-}→τ^{+}τ^{-}ϕ_{L}, ϕ_{L}→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 ϕ_{L} coupling to leptons in the range 0.04

Resonances in $e^+e^-$ annihilation near 2.2 GeV

Abstract: 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-→ωππ cross sections to investigate the nature of the resonance structure recently observed by the BESIII experiment in the e+e-→K+K- cross section.

Dalitz analysis of D0 →k-π+η decays at Belle

Abstract: We present the results of the first Dalitz plot analysis of the decay D0→K-π+η. The analysis is performed on a data set corresponding to an integrated luminosity of 953 fb-1 collected by the Belle detector at the asymmetric-energy e+e- KEKB collider. The Dalitz plot is well described by a combination of the six resonant decay channels K∗(892)0η, K-a0(980)+, K-a2(1320)+, K∗(1410)0η, K∗(1680)-π+ and K2∗(1980)-π+, together with Kπ and Kη S-wave components. The decays K∗(1680)-→K-η and K2∗(1980)-→K-η are observed for the first time. We measure ratio of the branching fractions, B(D0→K-π+η)B(D0→K-π+)=0.500±0.002(stat)±0.020(syst)±0.003(BPDG). Using the Dalitz fit result, the ratio B(K∗(1680)→Kη)B(K∗(1680)→Kπ) is measured to be 0.11±0.02(stat)-0.04+0.06(syst)±0.04(BPDG); this is much lower than the theoretical expectations (≈1) made under the assumption that K∗(1680) is a pure 13D1 state. The product branching fraction B(D0→[K2∗(1980)-→K-η]π+)=(2.2-1.9+1.7)×10-4 is determined. In addition, the πη′ contribution to the a0(980)± resonance shape is confirmed with 10.1σ statistical significance using the three-channel Flatte model. We also measure B(D0→K∗(892)0η)=(1.41-0.12+0.13)%. This is consistent with, and more precise than, the current world average (1.02±0.30)%, deviates with a significance of more than 3σ from the theoretical predictions of (0.51-0.92)%.

Measurement of two-particle correlations in hadronic $e^{+}e^{-}$ collisions at Belle

Abstract: The enhancement of charged-particle pairs with large pseudorapidity difference and small azimuthal angle difference, often referred to as the ``ridge signal'', is a phenomenon widely observed in high multiplicity proton-proton, proton-ion and deutron-ion collisions, which is not yet fully understood. In heavy-ion collisions, the hydrodynamic expansion of the Quark-Gluon Plasma is one of the possible explanations of the origin of the ridge signal. Measurements in the $e^+e^-$ collision system, without the complexities introduced by hadron structure in the initial state, can serve as a complementary probe to examine the formation of a ridge signal. The first measurement of two-particle angular correlation functions in high multiplicity $e^+e^-$ collisions at $\sqrt{s}=10.52$ GeV is reported. The hadronic $e^+e^-$ annihilation data collected by the Belle detector at KEKB are used in this study. Two-particle angular correlation functions are measured over the full azimuth and large pseudorapidity intervals which are defined by either the electron beam axis or the event thrust as a function of charged particle multiplicity. The measurement in the event thrust analysis, with mostly outgoing quark pairs determining the reference axis, is sensitive to the region of additional soft gluon emissions. No significant ridge signal is observed with either coordinates analyses. Near side jet correlations appear to be absent in the thrust axis analysis. The measurements are compared to predictions from various event generators and expected to provide new constraints to the phenomenological models in the low energy regime.

Search for Rare or Forbidden Decays of the D0 Meson

Abstract: We present a search for nine lepton-number-violating and three lepton-flavor-violating neutral charm decays of the type D^{0}→h^{'-}h^{-}l^{'+}l^{+} and D^{0}→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.

Precision Measurement of the Ratio B(ϒ(3S)→τ^{+}τ^{-})/B(ϒ(3S)→μ^{+}μ^{-}).

Abstract: We report on a precision measurement of the ratio ${\cal R}_{\tau\mu}^{\Upsilon(3S)} = {\cal B}(\Upsilon(3S)\to\tau^+\tau^-)/{\cal B}(\Upsilon(3S)\to\mu^+\mu^-)$ using data collected with the BaBar detector at the SLAC PEP-II $e^+e^-$ collider. The measurement is based on a 28 fb$^{-1}$ data sample collected at a center-of-mass energy of 10.355 GeV corresponding to a sample of 122 million $\Upsilon(3S)$ mesons. The ratio is measured to be ${\cal R}_{\tau\mu}^{\Upsilon(3S)} = 0.966 \pm 0.008_\mathrm{stat} \pm 0.014_\mathrm{syst}$ and is in agreement with the Standard Model prediction of 0.9948 within 2 standard deviations. The uncertainty in ${\cal R}_{\tau\mu}^{\Upsilon(3S)}$ is almost an order of magnitude smaller than the only previous measurement.

Search for lepton-flavor-violating decays D0 →x0e±μ

Abstract: Author(s): Lees, JP; Poireau, V; Tisserand, V; Grauges, E; Palano, A; Eigen, G; Brown, DN; Kolomensky, YG; Fritsch, M; Koch, H; Schroeder, T; Cheaib, R; Hearty, C; Mattison, TS; McKenna, JA; So, RY; Blinov, VE; Buzykaev, AR; Druzhinin, VP; Golubev, VB; Kozyrev, EA; Kravchenko, EA; Onuchin, AP; Serednyakov, SI; Skovpen, YI; Solodov, EP; Todyshev, KY; Lankford, AJ; Dey, B; Gary, JW; Long, O; Eisner, AM; Lockman, WS; Panduro Vazquez, W; Chao, DS; Cheng, CH; Echenard, B; Flood, KT; Hitlin, DG; Kim, J; Li, Y; Lin, DX; Miyashita, TS; Ongmongkolkul, P; Oyang, J; Porter, FC; Rohrken, M; Huard, Z; Meadows, BT; Pushpawela, BG; Sokoloff, MD; Sun, L; Smith, JG; Wagner, SR; Bernard, D; Verderi, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Fioravanti, E; Garzia, I; Luppi, E; Santoro, V; Calcaterra, A; De Sangro, R; Finocchiaro, G; Martellotti, S; Patteri, P; Peruzzi, IM; Piccolo, M; Rotondo, M; Zallo, A; Passaggio, S; Patrignani, C; Shuve, BJ; Lacker, HM; Bhuyan, B; Mallik, U; Chen, C; Cochran, J; Prell, S; Gritsan, AV; Arnaud, N; Davier, M | Abstract: We present a search for seven lepton-flavor-violating neutral charm meson decays of the type D0→X0e±μ, where X0 represents a π0, KS0, K∗0, ρ0, φ, ω, or η meson. The analysis is based on 468 fb-1 of e+e- annihilation data collected at or close to the (4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signals are observed, and we establish 90% confidence level upper limits on the branching fractions in the range (5.0-22.5)×10-7. The limits are between 1 and 2 orders of magnitude more stringent than previous measurements.

Measurement of Branching Fractions of $\Lambda_{c}^{+} \rightarrow \eta\Lambda\pi^{+}$, $\eta \Sigma^{0} \pi^{+}$, $\Lambda(1670) \pi^{+}$, and $\eta \Sigma(1385)^{+}$

Abstract: We report branching fraction measurements of four decay modes of the $\Lambda_{c}^{+}$ baryon, each of which includes an $\eta$ meson and a $\Lambda$ baryon in the final state, and all of which are measured relative to the $\Lambda_{c}^{+} \rightarrow p K^{-} pi^{+}$ decay mode. The results are based on a $980~\mathrm{fb^{-1}}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. Two decays, $\eta \Sigma^{0} \pi^{+}$ and $\Lambda(1670) \pi^{+}$, are observed for the first time, while the measurements of the other decay modes, $\Lambda_{c}^{+} \rightarrow \eta\Lambda\pi^{+}$ and $\eta\Sigma(1385)^{+}$, are more precise than those made previously. We obtain $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \eta \Lambda \pi^{+})/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $0.293 \pm 0.003 \pm 0.014$, $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \eta \Sigma^{0} \pi^{+})/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $0.120 \pm 0.006 \pm 0.006$, $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \Lambda(1670) \pi^{+}) \times \mathcal{B}(\Lambda(1670) \rightarrow \eta \Lambda)/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $(5.54 \pm 0.29 \pm 0.73 ) \times 10^{-2}$, and $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \eta \Sigma(1385)^{+})/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $0.192 \pm 0.006 \pm 0.016$. The mass and width of the $\Lambda(1670)$ are also precisely determined to be $1674.3 \pm 0.8 \pm 4.9~{\rm MeV}/c^{2}$ and $36.1 \pm 2.4 \pm 4.8~{\rm MeV}$, respectively, where the uncertainties are statistical and systematic, respectively.

First search for the $\eta_{c2}(1D)$ in $B$ decays at Belle

Abstract: The first dedicated search for the $\eta_{c2}(1D)$ is carried out using the decays $B^+ \rightarrow \eta_{c2}(1D) K^+$, $B^0 \rightarrow \eta_{c2}(1D) K^0_S$, $B^0 \rightarrow \eta_{c2}(1D) \pi^- K^+$, and $B^+ \rightarrow \eta_{c2}(1D) \pi^+ K^0_S$ with $\eta_{c2}(1D) \to h_c \gamma$. No significant signal is found. For the $\eta_{c2}(1D)$ mass range between $3795$ and $3845\ \mathrm{MeV}/c^2$, the branching-fraction upper limits are determined to be $\mathcal{B}(B^+ \rightarrow \eta_{c2}(1D) K^+) \times \mathcal{B}(\eta_{c2}(1D) \to h_c \gamma) < 3.7 \times 10^{-5}$, $\mathcal{B}(B^0 \rightarrow \eta_{c2}(1D) K^0_S) \times \mathcal{B}(\eta_{c2}(1D) \to h_c \gamma) < 3.5 \times 10^{-5}$, $\mathcal{B}(B^0 \rightarrow \eta_{c2}(1D) \pi^- K^+) \times \mathcal{B}(\eta_{c2}(1D) \to h_c \gamma) < 1.0 \times 10^{-4}$, and $\mathcal{B}(B^+ \rightarrow \eta_{c2}(1D) \pi^+ K^0_S) \times \mathcal{B}(\eta_{c2}(1D) \to h_c \gamma) < 1.1 \times 10^{-4}$ at 90% C. L. The analysis is based on the 711 $\mathrm{fb}^{-1}$ data sample collected on the $\Upsilon(4S)$ resonance by the Belle detector, which operated at the KEKB asymmetric-energy $e^+ e^-$ collider.

Study of B →p p ππ STUDY of B →p p ππ CHU K. et al.

Abstract: We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, the KEK computer group and the Pacific Northwest National Laboratory (PNNL) Environmental Molecular Sciences Laboratory (EMSL) computing group for strong computing support, and the National Institute of Informatics and Science Information NETwork 5 (SINET5) for valuable network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan, the Japan Society for the Promotion of Science (JSPS), and the Tau-Lepton Physics Research Center of Nagoya University; the Australian Research Council including Grants No. DP180102629, No. DP170102389, No. DP170102204, No. DP150103061, and No. FT130100303; the Austrian Science Fund (FWF); the National Natural Science Foundation of China under Contracts No. 11435013, No. 11475187, No. 11521505, No. 11575017, No. 11675166, and No. 11705209; the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS), Grant No. QYZDJ-SSW-SLH011; the CAS Center for Excellence in Particle Physics (CCEPP); the Shanghai Pujiang Program under Grant No. 18PJ1401000; the Ministry of Education, Youth and Sports of the Czech Republic under Contract No. LTT17020; the Carl Zeiss Foundation, the Deutsche Forschungsgemeinschaft, the Excellence Cluster Universe, and the VolkswagenStiftung; the Department of Science and Technology of India; the Istituto Nazionale di Fisica Nucleare of Italy; the National Research Foundation (NRF) of Korea under Grants No. 2015H1A2A1033649, No. 2016R1D1A1B01010135, No. 2016K1A3A7A09005 603, No. 2016R1D1A1B02012900, No. 2018R1A2B3003 643, No. 2018R1A6A1A06024970, and No. 2018R1D1 A1B07047294; the Radiation Science Research Institute, Foreign Large-size Research Facility Application Supporting project, the Global Science Experimental Data Hub Center of theKorea Institute of Science and Technology Information and KREONET/GLORIAD; the Polish Ministry of Science and Higher Education and the National Science Center; the Grant of the Russian Federation Government, Agreement No. 14.W03.31.0026; the Slovenian Research Agency; Ikerbasque, Basque Foundation for Science, Spain; the Swiss National Science Foundation; the Ministry of Education and the Ministry of Science and Technology of Taiwan; and the United States Department of Energy and the National Science Foundation.

Exclusive $B^0 \to \pi^- \ell^+ \nu_\ell$ Decays with Hadronic Full Event Interpretation Tagging in 34.6 fb$^{-1}$ of Belle II Data

Abstract: We present the results of the re-discovery of the decay $B^0 \to \pi^- \ell^+ u_\ell$ in 34.6 fb$^{-1}$ of Belle II data using hadronic $B$-tagging via the Full Event Interpretation algorithm. We observe 21 signal events on a background of 155 in a fit to the distribution of the square of the missing mass, $M_{\mathrm{miss}}^2$, with a significance of 5.69$\sigma$, and determine a total branching fraction of (1.58 $\pm$ 0.43$_{\mathrm{stat}}$ $\pm$ 0.07$_{\mathrm{sys}}$) $\times 10^{-4}$.

Search for transitions from (4S) and (5S) to ηb (1S) and ηb (2S) with emission of an ω meson

Abstract: Using data collected in the Belle experiment at the KEKB asymmetric-energy e+e− collider we search for transitions Υ(4S)→ η$_{b}$(1S)ω, Υ(5S)→η$_{b}$(1S)ω and Υ(5S)→η$_{b}$(2S)ω. No significant signals are observed and we set 90% confidence level upper limits on the corresponding visible cross sections: 0.2 pb, 0.4 pb and 1.9 pb, respectively.

A calibration of the Belle II hadronic tag-side reconstruction algorithm with $B \rightarrow X\ell \nu$ decays.

Abstract: Tag-side reconstruction is an important method for reconstructing $B$ meson decays with missing energy. The Belle II tag-side reconstruction algorithm, Full Event Interpretation, relies on a hierarchical reconstruction of $B$ meson decays with multivariate classification employed at each stage of reconstruction. Given the large numbers of classifiers employed and decay chains reconstructed, the performance of the algorithm on data and simulation differs significantly. Here, calibration factors are derived for hadronic tag-side $B$ decays by measuring a signal side decay, $B \rightarrow X\ell u$, in $34.6$ fb$^{-1}$ of Belle II data. For a very loose selection on the tag-side $B$ multivariate classifier, the calibration factors are $0.65 \pm 0.02$ and $0.83 \pm 0.03$ for tag-side $B^{+}$ and $B^{0}$ mesons, respectively.

Measurement of the semileptonic $\bar{B}^0 \to D^{*+} \ell^{-} \nu_{\ell}$ branching fraction with fully reconstructed $B$ meson decays and 34.6 fb$^{-1}$of Belle II data

Abstract: We present a first measurement of the $\bar{B^{0}} \rightarrow D^{*+} \ell^{-} u_{\ell}$ branching fraction using fully reconstructed $B$ meson decays employing the Full Event Interpretation algorithm. Collision events corresponding to an integrated luminosity of \lumi are analyzed, which were recorded by the Belle~II detector operated at the SuperKEKB accelerator complex. We measure$\cal{B}(\bar{B^{0}} \rightarrow D^{*+} \ell^{-} u_{\ell}) =4.51 \pm 0.41_{stat}\pm0.27_{syst} \pm0.45_{\pi_s}$, with the first and second error denoting the statistical and systematic uncertainty, respectively, and the third dominant uncertainty is from the slow pion reconstruction efficiency.