Search for Evidence of Baryogenesis and Dark Matter in B

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

Search for Darkonium in e

Collider searches for dark sectors, new particles interacting only feebly with ordinary matter, have largely focused on identifying signatures of new mediators, leaving much of dark sector structures unexplored. In particular, the existence of dark matter bound states (darkonia) remains to be investigated. This possibility could arise in a simple model in which a dark photon (A^{'}) is light enough to generate an attractive force between dark fermions. We report herein a search for a J^{PC}=1^{--} darkonium state, the ϒ_{D}, produced in the reaction e^{+}e^{-}→γϒ_{D}, ϒ_{D}→A^{'}A^{'}A^{'}, where the dark photons subsequently decay into pairs of leptons or pions, using 514 fb^{-1} of data collected with the BABAR detector. No significant signal is observed, and we set bounds on the γ-A^{'} kinetic mixing as a function of the dark sector coupling constant for 0.001

Search for an Axionlike Particle in B Meson Decays.

Axionlike particles (ALPs) are predicted in many extensions of the standard model, and their masses can naturally be well below the electroweak scale. In the presence of couplings to electroweak bosons, these particles could be emitted in flavor-changing B meson decays. We report herein a search for an ALP, a, in the reaction B^{±}→K^{±}a, a→γγ using data collected by the BABAR experiment at SLAC. No significant signal is observed, and 90% confidence level upper limits on the ALP coupling to electroweak bosons are derived as a function of ALP mass, improving current constraints by several orders of magnitude in the range 0.175 GeV

Search for Lepton Flavor Violation in ϒ(3S)→e

We report on the first search for electron-muon lepton flavor violation (LFV) in the decay of a b quark and b antiquark bound state. We look for the LFV decay ϒ(3S)→e^{±}µ^{∓} in a sample of 118 million ϒ(3S) mesons from 27 fb^{-1} of data collected with the BABAR detector at the SLAC PEP-II e^{+}e^{-} collider operating with a 10.36 GeV center-of-mass energy. No evidence for a signal is found, and we set a limit on the branching fraction B[ϒ(3S)→e^{±}µ^{∓}]<3.6×10^{-7} at 90% C. L. This result can be interpreted as a limit Λ_{NP}/g_{NP}^{2}>80 TeV on the energy scale Λ_{NP} divided by the coupling-squared g_{NP}^{2} of relevant new physics (NP).

Measurements of the Absolute Branching Fractions of B

A study of the two-body decays B^{±}→X_{cc[over ¯]}K^{±}, where X_{cc[over ¯]} 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.

Search for a Dark Leptophilic Scalar in e

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

Precision Measurement of the Ratio B(ϒ(3S)→τ

We report on a precision measurement of the ratio R_{τµ}^{ϒ(3S)}=B(ϒ(3S)→τ^{+}τ^{-})/B(ϒ(3S)→µ^{+}µ^{-}) 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 ϒ(3S) mesons. The ratio is measured to be R_{τµ}^{ϒ(3S)}=0.966±0.008_{stat}±0.014_{syst} and is in agreement with the standard model prediction of 0.9948 within 2 standard deviations. The uncertainty in R_{τµ}^{ϒ(3S)} is almost an order of magnitude smaller than the only previous measurement.

Search for Rare or Forbidden Decays of the D

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.

Extraction of form Factors from a Four-Dimensional Angular Analysis of B[over ¯]→D

An angular analysis of the decay B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}, ℓ∈{e,µ}, is reported using the full e^{+}e^{-} collision data set collected by the BABAR experiment at the ϒ(4S) resonance. One B meson from the ϒ(4S)→BB[over ¯] decay is fully reconstructed in a hadronic decay mode, which constrains the kinematics and provides a determination of the neutrino momentum vector. The kinematics of the semileptonic decay is described by the dilepton mass squared, q^{2}, and three angles. The first unbinned fit to the full four-dimensional decay rate in the standard model is performed in the so-called Boyd-Grinstein-Lebed approach, which employs a generic q^{2} parametrization of the underlying form factors based on crossing symmetry, analyticity, and QCD dispersion relations for the amplitudes. A fit using the more model-dependent Caprini-Lellouch-Neubert (CLN) approach is performed as well. Our form factor shapes show deviations from previous fits based on the CLN parametrization. The latest form factors also provide an updated prediction for the branching fraction ratio R(D^{*})≡B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ})=0.253±0.005. Finally, using the well-measured branching fraction for the B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ} decay, a value of |V_{cb}|=(38.36±0.90)×10^{-3} is obtained that is consistent with the current world average for exclusive B[over ¯]→D^{(*)}ℓ^{-}ν[over ¯]_{ℓ} decays and remains in tension with the determination from inclusive semileptonic B decays to final states with charm.

Study of CP asymmetry in B

We present a measurement of the asymmetry A_{CP} between same-sign inclusive dilepton samples ℓ^{+}ℓ^{+} and ℓ^{-}ℓ^{-} (ℓ=e, µ) from semileptonic B decays in ϒ(4S)→BB[over ¯] events, using the complete data set recorded by the BABAR experiment near the ϒ(4S) resonance, corresponding to 471×10^{6} BB[over ¯] pairs. The asymmetry A_{CP} allows comparison between the mixing probabilities P(B[over ¯]^{0}→B^{0}) and P(B^{0}→B[over ¯]^{0}), and therefore probes CP and T violation. The result, A_{CP}=[-3.9±3.5(stat)±1.9(syst)]×10^{-3}, is consistent with the standard model expectation.

Search for Long-Lived Particles in e+ e- Collisions.

We present a search for a neutral, long-lived particle L that is produced in e+ e- collisions and decays at a significant distance from the e+ e- interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an e+ e- data sample with a luminosity of 489.1 fb(-1) collected by the BABAR detector at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and just below the ϒ(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible two-body L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction B(B→XsL), where Xs is a strange hadronic system.

Search for a dark photon in e(+)e(-) collisions at BABAR.

Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the so-called dark photon (A^{'}), connecting the dark sector to the standard model. We present a search for a dark photon in the reaction e^{+}e^{-}→γA^{'}, A^{'}→e^{+}e^{-}, µ^{+}µ^{-} using 514 fb^{-1} of data collected with the BABAR detector. We observe no statistically significant deviations from the standard model predictions, and we set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of 10^{-4}-10^{-3} for dark photon masses in the range 0.02-10.2 GeV. We further constrain the range of the parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon.

Search for CP violation in B0-B0 mixing using partial reconstruction of B0→D*- Xℓ+ νℓ and a kaon tag.

We present results of a search for CP violation in B0- B0 mixing with the BABAR detector. We select a sample of B0→D*- Xℓ+ ν decays with a partial reconstruction method and use kaon tagging to assess the flavor of the other B meson in the event. We determine the CP violating asymmetry ACP≡[N(B0B0)-N(B0B0)]/[N(B0B0)+N(B0B0)]=(0.06±0.17(-0.32)(+0.38))%, corresponding to ΔCP=1-|q/p|=(0.29±0.84(-1.61)(+1.88))×10(-3).

Measurement of the D*(2010)+ meson width and the D*(2010)+ - D0 mass difference.

We measure the mass difference Δm0 between the D*(2010)+ and the D0 and the natural linewidth Γ of the transition D*(2010)+ → D0π+. The data were recorded with the BABAR detector at center-of-mass energies at and near the Υ(4S) resonance, and correspond to an integrated luminosity of approximately 477 fb(-1). The D0 is reconstructed in the decay modes D0 → K- π+ and D0 → K- π+ π- π+. For the decay mode D0 → K- π+ we obtain Γ = (83.4±1.7±1.5) keV and Δm0 = (145425.6±0.6±1.7) keV, [corrected] where the quoted errors are statistical and systematic, respectively. For the D0 → K- π+ π- π+ mode we obtain Γ = (83.2±1.5±2.6) keV and Δm0 = (145426.6±0.5±1.9) keV. [corrected] The combined measurements yield Γ = (83.3±1.2±1.4) keV and Δm0 = (145425.9±0.4±1.7) keV; the width is a factor of approximately 12 times more precise than the previous value, while the mass difference is a factor of approximately 6 times more precise.

Presentation of primary hyperparathyroidism due to adenoma.

This descriptive study was done to evaluate the clinical, biochemical and radiological findings of primary hyperthyroidism (pHPT) patients with parathyroid adenoma. This study was done in the department of Otolaryngology and Head-Neck surgery, BIRDEM, Dhaka from July 2000 to June 2007. We retrospectively reviewed the clinical presentation, biochemical and radiological features from the case records from the last 7 years of 32 patients at a tertiary care centre in Dhaka who had documented pHPT due to adenoma. Of them 18 were male and 14 were female. Mean age±SD of the patients was 42.16±11.64 years. Median preoperative serum calcium, serum phosphate and serum parathyroid hormone (PTH) levels were 11.42 mg/dL (range 8.4-14.0mg/dL), 3.11 mg/dL (range 2.5-4.5) and 293.22 pg/mL (range 65-700 pg/mL), respectively. Of all patients 75% had raised serum calcium level and 100.0% had raised serum PTH levels but all had normal serum phosphate level. Common radiological features were nephrocalcinosis, renal calculi, osteopenic changes in finger and toe, Brown tumour in forearm, 'Salt and pepper' appearance in skull, fracture of femur, fracture radius. pHPT due to adenoma in Bangladesh continues to be a symptomatic disorder with skeletal and renal manifestations.

Measurement of the neutron F2 structure function via spectator tagging with CLAS.

We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲100 MeV/c and their angles to ≳100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65

Bis(2,S-dimethyl-dithio-carbazate-κ(2)N(3),S)(nitrato-κO)copper(II) nitrate.

The title complex, [Cu(NO(3))(C(3)H(8)N(2)S(2))(2)]NO(3), represents a low-symmetry polymorph (P-1, Z = 4) of a previously reported form [P-1, Z = 2; Ali et al. (2011 ▶). Polyhedron, 30, 542-548]. The Cu(II) atom in each independent cation is found within a distorted square-pyramidal N(2)S(2)O coordination geometry defined by two N,S-bidentate ligands and an O atom derived from a monodentate nitrate. The primary difference between the cations is found in the relative orientations of the coordinated nitrate groups, which are directed to opposite sides of the mol-ecule. Supra-molecular layers along [110] and sustained by N-H⋯O inter-actions feature in the crystal packing. These are connected along the c axis by C-H⋯O inter-actions.

Benzyl 2-methyl-3-[(E)-(thio-phen-2-yl)methyl-idene]dithio-carbazate.

In the title compound, C(14)H(14)N(2)S(3), the thione S atom and methyl group are syn, as are the two thio-ether S atoms. The mol-ecule is twisted, the dihedral angles between the central (C(2)N(2)S(2)) residue and the pendent 2-thienyl and phenyl rings being 21.57 (6) and 77.54 (3)°, respectively. In the crystal, mol-ecules assemble into a three-dimensional architecture via C-H⋯π inter-actions, involving both the five- and six-membered rings as acceptors, as well as S⋯S inter-actions [3.3406 (5) Å] between centrosymmetrically related 2-thienyl rings.

Chest HRCT Severity Scores among Hospitalized Patients with COVID-19.

Corona Virus Disease 2019 (COVID-19) was declared a pandemic in March 2020. This global health crisis caused thousands of pneumonia related death all over the world since December 2019. RT-PCR is the primary test for diagnosis of COVID-19, though its sensitivity and specificity is variable. Several studies revealed that chest HRCT complements RT-PCR in highly suspected cases or in false negative RT-PCR and helps to gauge disease severity. This study was carried out with an aim to find out the severity scores of chest HRCT in hospitalized patients with COVID-19. This cross sectional descriptive type of observational study was carried out at COVID-19 unit of Sylhet Women's Medical College Hospital, Bangladesh from April 2021 to September 2021. Data were collected from purposively selected 204 patients with COVID-19 by face to face interview, chest HRCT and necessary laboratory investigations. Informed written consent was taken from the participants of the study at the beginning of the interview. Data were analyzed by using SPSS version 21.0. The results of the study showed that mean age of the patients with COVID-19 was 57.9 years with a standard deviation of ±15.8 years. Majority of them (121, 59.3%) were female and the remaining (83, 40.7%) were male. Regarding co-morbidities it was found that each 115 (56.4%) patients were hypertensive and diabetic. Thirty five (16.2%) had ischemic heart disease; 3(1.5%) had congestive cardiac failure and 2(1.0%) had asthma. One (0.5%) patient has atrial fibrillation. In case of 160(78.4%) RT-PCR confirmed patients with COVID-19, chest HRCT was found positive and in 44(21.6%) it was found negative. Among the positive cases mild (7 or less) chest HRCT score was found in 26(12.7%) patients; moderate (8-17) score was found in highest number of patients (128, 62.7%) and severe (18 or more) chest HRCT score was found in 6(2.9%) patients with COVID-19. Chi-square test was carried out to assess the relation of chest HRCT scores with age group, sex, troponin-I, D-Dimer and clinical outcomes within CCU but statistically significant relation was not found (p>0.05). The negative scans were highest (20, 9.8%) in the age group of 41-60 years. Mild, moderate and severe chest HRCT scores was found highest in the age group of 61-80 years (13, 6.4%; 51, 25.0% and 5, 2.5% respectively) (p=0.508). Chest HRCT scans were negative in 18(8.8%) male and 26(12.7%) female. Mild scores were equally distributed between each sex i.e. male 13(6.4%) and female 13(6.4%). Both moderate and severe scores were found more in female (77, 37.7% and 5, 2.5% respectively) than male (51, 25.0% and 1, 0.5% respectively) (p=0.492). Negative chest HRCT scans, mild, moderate and severe scores-all were found more in patients with elevated D-Dimer (p=0.194). Among 204 patients one (0.5%) died in the CCU who had mild score of chest HRCT (p=0.076) but highly elevated Troponin-I (21.70ng/mL). Chest HRCT was found positive among 78.4% of patients with COVID-19 confirmed by RT-PCR. Chest HRCT can help physicians to detect suspected cases and to assess the severity and outcome of the disease. However, further research is recommended to clarify the role of chest HRCT in assessing severity of COVID-19 and prediction of prognosis.

Mechanisms of donor-specific tolerance in recipients of haploidentical combined bone marrow/kidney transplantation.

We recently reported long-term organ allograft survival without ongoing immunosuppression in four of five patients receiving combined kidney and bone marrow transplantation from haploidentical donors following nonmyeloablative conditioning. In vitro assays up to 18 months revealed donor-specific unresponsiveness. We now demonstrate that T cell recovery is gradual and is characterized by memory-type cell predominance and an increased proportion of CD4⁺ CD25⁺ CD127⁻ FOXP3⁺ Treg during the lymphopenic period. Complete donor-specific unresponsiveness in proliferative and cytotoxic assays, and in limiting dilution analyses of IL-2-producing and cytotoxic cells, developed and persisted for the 3-year follow-up in all patients, and extended to donor renal tubular epithelial cells. Assays in two of four patients were consistent with a role for a suppressive tolerance mechanism at 6 months to 1 year, but later (≥ 18 months) studies on all four patients provided no evidence for a suppressive mechanism. Our studies demonstrate, for the first time, long-term, systemic donor-specific unresponsiveness in patients with HLA-mismatched allograft tolerance. While regulatory cells may play an early role, long-term tolerance appears to be maintained by a deletion or anergy mechanism.