arXiv subjects

E. Gabathuler

Publications and source records attributed to E. Gabathuler.

6 recordsLinked to original sources

arXiv2023

Search for $B$ Mesogenesis at BABAR

A new mechanism has been proposed to simultaneously explain the presence of dark matter and the matter-antimatter asymmetry in the universe. This scenario predicts exotic $B$ meson decays into a baryon and a dark sector anti-baryon ($\psi_D$) with branching fractions accessible at $B$ factories. We present a search for $B \rightarrow \Lambda \psi_D$ decays using data collected by the $BABAR$ experiment at SLAC. This reaction is identified by fully reconstructing the accompanying $B$ meson and requiring the presence of a single $\Lambda$ baryon in the remaining particles. No significant signal is observed, and bounds on the $B \rightarrow \Lambda \psi_D$ branching fraction are derived in the range $0.13 - 5.2\times 10^{-5}$ for $1.0 < m_{\psi_D} < 4.2$ GeV/$c^{2}$. These results set strong constraints on the parameter space allowed by the theory.

hep-ex↗

arXiv2020

Search for lepton-flavor violating decays $D^{0}\rightarrow X^{0}e^{\pm}μ^{\mp}$

We present a search for seven lepton-flavor-violating neutral charm decays of the type $D^{0}\rightarrow X^{0} e^{\pm} μ^{\mp}$, where $X^{0}$ represents a $π^{0}$, $K^{0}_{\rm S}$, $\bar{K^{*0}}$, $ρ^{0}$, $ϕ$, $ω$, or $η$ meson. 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 signals are observed, and we establish 90\% confidence level upper limits on the branching fractions in the range $(5.0 - 22.5)\times 10^{-7}$. The limits are between one and two orders of magnitude more stringent than previous measurements.

hep-ex↗

arXiv2020

Precision measurement of the ${\cal B}(\Upsilon(3S)\to\tau^+\tau^-)/{\cal B}(\Upsilon(3S)\to\mu^+\mu^-)$ ratio

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.

hep-ex↗

arXiv2020

Search for rare or forbidden decays of the $D^{0}$ meson

We present a search for nine lepton-number-violating and three lepton-flavor-violating neutral charm decays of the type $D^0\rightarrow h^{\prime -} h^{-}\ell^{\prime +} \ell^{+}$ and $D^0\rightarrow h^{\prime -} h^{+}\ell^{\prime\pm} \ell^{\mp}$, where $h$ and $h^{\prime}$ represent a $K$ or $π$ meson and $\ell$ and $\ell^{\prime}$ an electron or muon. The analysis is based on $468$ fb$^{-1}$ of $e^+e^-$ annihilation data collected at or close to the $Y(4S)$ 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 $(1.0 - 30.6)\times 10^{-7}$. The limits are between one and three orders of magnitude times more stringent than previous measurements.

hep-ex↗

arXiv2019

Search for $B^- \to Λ\bar p ν\barν$ with the BABAR experiment

We search for the rare flavor-changing neutral current process $B^- \to Λ{\overline p} ν{\overlineν}$ using data from the BABAR experiment. A total of 424 fb$^{-1}$ of $e^+e^-$ collision data collected at the center-of-mass energy of the $Υ$(4S) resonance is used in this study, corresponding to a sample of ${(471 \pm 3) \times 10^{6}}$ $B\overline{B}$ pairs. Signal $B^- \to Λ{\overline p} ν{\overlineν}$ candidates are identified by first fully reconstructing a $B^+$ decay in one of many possible exclusive decays to hadronic final states, then examining detector activity that is not associated with this reconstructed $B^+$ decay for evidence of a signal $B^- \to Λ{\overline p} ν{\overlineν}$ decay. The data yield is found to be consistent with the expected background contribution under a null signal hypothesis, resulting in an upper limit of ${{\cal B} (B^- \to Λ{\overline p} ν{\overlineν}) < 3.0\times 10^{-5}}$ at the $90\%$ confidence level.

hep-ex↗

arXiv2017

Determination of the strong coupling constant $\alpha_s(M_Z)$ in next-to-next-to-leading order QCD using H1 jet cross section measurements

The strong coupling constant $\alpha_s(M_Z)$ is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic $ep$ scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of $\alpha_s(M_Z)$ at the $Z$-boson mass $m_Z$ are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be $\alpha_s(M_Z)=0.1166\,(19)_{\rm exp}\,(24)_{\rm th}$. Complementary, $\alpha_s(M_Z)$ is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value $\alpha_s(M_Z)=0.1147\,(25)_{\rm tot}$ obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.

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