An 18-year-old male without prior medical history developed fulminant myocarditis concomitant to severe COVID-19 pneumonia, which was confirmed using serial cardiac magnetic resonance. This may have ...important diagnostic, monitoring, and pathogenic implications. (Level of Difficulty: Intermediate.)
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An 18-year-old man without prior medical history developed fulminant myocarditis concomitant to severe COVID-19 pneumonia, which was confirmed…
We calculate the two-loop contributions to the electric dipole moments of the electron and the neutron mediated by charged Higgs in a generic supersymmetric theories. The new contributions are ...originated from the potential CP violation in the trilinear couplings of the charged Higgs bosons to the scalar-top or the scalar-bottom quarks. These couplings did not receive stringent constraints directly. We find observable effects for a sizable portion of the parameter space related to the third generation scalar-quarks in the minimal supersymmetric standard model.
Measurements are presented of R_b, the ratio of the b bbar cross-section to the q qbar cross-section in e+e- collisions, and the forward-backward asymmetry A^b_FB at twelve energy points in the range ...sqrt(s) = 130-207 GeV. These results are found to be consistent with the Standard Model expectations. The measurements are used to set limits on new physics scenarios involving contact interactions.
A measurement of the W boson mass and width has been performed by the DELPHI collaboration using the data collected during the full LEP2 programme (1996-2000). The data sample has an integrated ...luminosity of 660 pb^-1 and was collected over a range of centre-of-mass energies from 161 to 209 GeV. Results are obtained by applying the method of direct reconstruction of the mass of the W from its decay products in both the W+W- -> lvqq and W+W- -> qqqq channels. The W mass result for the combined data set is M_W = 80.336 +/- 0.055 (Stat.) +/- 0.028 (Syst.) +/- 0.025 (FSI) +/- 0.009 (LEP) GeV/c^2, where FSI represents the uncertainty due to final state interaction effects in the qqqq channel, and LEP represents that arising from the knowledge of the collision energy of the accelerator. The combined value for the W width is Gamma_W = 2.404 +/- 0.140 (Stat.) +/- 0.077 (Syst.) +/- 0.065 (FSI) GeV/c^2. These results supersede all values previously published by the DELPHI collaboration. This paper is dedicated to the memory of Carlo Caso.
Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qqbar disintegrations of the Z^0 were studied in the kinematic range 0.2 < E_gamma < 1 GeV and ...transverse momentum with respect to the closest jet direction p_T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10^{-3} gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) x 10^{-3} gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.
The charmed strange baryon Xi_c^0 was searched for in the decay channel Xi_c^0 -> Xi- pi+, and the beauty strange baryon Xi_b in the inclusive channel Xi_b -> Xi- l- anti-nu X, using the 3.5 million ...hadronic Z events collected by the DELPHI experiment in the years 1992--1995. The Xi- was reconstructed through the decay Xi- -> Lambda pi-, using a constrained fit method for cascade decays. An iterative discriminant analysis was used for the Xi_c^0 and Xi_b selection. The production rates were measured to be f_{Xi_c^0} x BR(Xi_c^0 -> Xi- pi+)= (4.7 +/- 1.4 (stat.) +/- 1.1 (syst.))10^{-4} per hadronic Z decay, and BR(b -> Xi_b) x BR(Xi_b -> Xi- l- X)= (3.0 +/- 1.0 (stat.) +/- 0.3 (syst.))10^{-4} for each lepton species (electron or muon). The lifetime of the Xi_b baryon was measured to be tau_{Xi_b} = 1.45{^{+0.55}_{-0.43}} (stat.) +/- 0.13 (syst.) ps. A combination with the previous DELPHI lifetime measurement gives tau_{Xi_b} = 1.48{^{+0.40}_{-0.31}} (stat.) +/- 0.12 (syst.) ps.
The form factor of Λ0 b baryons is estimated using 3.46×106 hadronic Z decays collected by the DELPHI experiment between 1992 and 1995. Charmed Λ+c baryons fully reconstructed in the pK−π+, pK0 S, ...and Λπ+π+π− modes, are associated to a lepton with opposite charge in order to select Λ0 b →Λ+c l−¯νl decays. From a combined likelihood and event rate fit to the distribution of the Isgur–Wise variable w, and using the Heavy Quark Effective Theory (HQET), the slope of the b-baryon form factor is measured to be ˆ ρ2 = 2.03 ± 0.46(stat)+0.72−1.00(syst). The exclusive semileptonic branching fraction Br(Λ0 b →Λ+c l−¯νl ) can be derived from ˆ ρ2 and is found to be (5.0+1.1−0.8(stat)+1.6−1.2 (syst))%. Limits on other branching fractions are also obtained.
Searches for pair-production of supersymmetric particles under the assumption of non-conservation of R-parity with a dominant LLEbar or UbarDbarDbar term have been performed using the data collected ...by the DELPHI experiment at LEP in e+e- collisions at centre-of-mass energies from 192 up to 208 GeV. No excess of data above Standard Model expectations was observed. The results were used to constrain the MSSM parameter space and to derive limits on the masses of supersymmetric particles.
The forward-backward asymmetries of the processes $e^+e^- \rightarrow Z \rightarrow b \overline{b}$ and $e^+e^- \rightarrow Z \rightarrow c \overline{c}$ were measured from a sample of hadronic ...Zdecays collected by the DELPHI experiment between 1993 and 1995. Enriched samples of $b\bar{b}$ and $c\bar{c}$ events were obtained using lifetime information. The tagging of b and c quarks in these samples was based on the semileptonic decay channels $b/c \rightarrow X + \mu $ and $ b/c \rightarrow X + e $ combined with charge flow information from the hemisphere opposite to the lepton. Combining the $A_{\mathrm{FB}}^{\mathrm{b\overline{\mathrm{b}}}$ and $A_{\mathrm{FB}}^{\mathrm{c\overline{\mathrm{c}}}$ measurements presented in this paper with published results based on 1991 and 1992 DELPHI data samples, the following pole asymmetries were obtained: \begin{displaymath}\mbox{$A_{\mathrm{FB}}^{\mathrm{0, b}}$}= 0.1021 \pm 0.0052 \mathrm{~(stat)} \pm 0.0024 \mathrm{~(syst)} \end{displaymath} \begin{displaymath}\mbox{$A_{\mathrm{FB}}^{\mathrm{0, c}}$}= 0.0728 \pm 0.0086 \mathrm{~(stat)} \pm 0.0063 \mathrm{~(syst)}\end{displaymath} The effective value of the weak mixing angle derived from these measurements is \begin{displaymath}\mbox{$\sin ^2 \theta_{\mathrm{W,eff}}^{\mathrm{lept}}$}= 0.23170 \pm 0.00097 .\end{displaymath}
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