ترغب بنشر مسار تعليمي؟ اضغط هنا

Experimental Status of b --> s(d) gamma Decays

144   0   0.0 ( 0 )
 نشر من قبل Francesca DiLodovico
 تاريخ النشر 2003
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

Radiative penguin decays provide an indirect probe for physics beyond the Standard Model and contribute to the determination of the CKM matrix elements. Copious quantities of B mesons produced at the B-Factories permit precision measurements of radiative penguin decays. We review the experimental status of the radiative penguin processes b --> s(d) gamma.



قيم البحث

اقرأ أيضاً

The decay mode $B^{0}_{s} to D^{mp}_{s} K^{pm} $ allows for one of the theoretically cleanest measurements of the CKM angle $gamma$ through the study of time-dependent $ensuremath{CP}xspace$ violation. This paper reports a measurement of its branchin g fraction relative to the Cabibbo-favoured mode $B^{0}_{s} to D^{-}_{s} pi^{+}$ based on a data sample of 0.37 fb$^{-1}$ proton-proton collisions at $sqrt{s} = 7$ TeV collected in 2011 with the LHCb detector. In addition, the ratio of $ensuremath{mathrm{B}}xspace$ meson production fractions $ensuremath{f_s/f_d}$, determined from semileptonic decays, together with the known branching fraction of the control channel $B^{0} to D^{-} pi^{+}$, is used to perform an absolute measurement of the branching fractions: $B (B^0_s to D^-_s pi^+) ;= (2.95 pm 0.05 pm 0.17^{,+,0.18}_{,-,0.22}) times 10^{-3}$, $B (B^0_s to D^mp_s K^pm) = (1.90 pm 0.12 pm 0.13^{,+,0.12}_{,-,0.14}) times 10^{-4},$, where the first uncertainty is statistical, the second the experimental systematic uncertainty, and the third the uncertainty due to $f_s/f_d$.
We present measurements of branching fractions and CP asymmetries of several B- -> D(*)0 K(*)- decays, with the D(*)0 decaying to CP-even, CP-odd, and flavor eigenstates, that can constrain the CP angle gamma as well as the amplitude ratio rb=A(B -> u)/A(B -> c), using methods proposed by Gronau, London and Wyler or Atwood, Dunietz and Sony. We use data collected with the BABAR detector at the PEP-II asymmetric energy e+e- collider at SLAC.
The polarization of photons produced in radiative $B^{0}_{s}$ decays is studied for the first time. The data are recorded by the LHCb experiment in $pp$ collisions corresponding to an integrated luminosity of 3fb$^{-1}$ at center-of-mass energies of $7$ and $8$TeV. A time-dependent analysis of the $B^{0}_{s} to phi gamma$ decay rate is conducted to determine the parameter ${mathcal{A}}^Delta$, which is related to the ratio of right- over left-handed photon polarization amplitudes in $b to s gamma$ transitions. A value of ${mathcal{A}}^Delta=-0.98^{,+0.46,+0.23}_{,-0.52,-0.20}$ is measured. This result is consistent with the Standard Model prediction within two standard deviations.
We describe a measurement of the direct CP asymmetry between inclusive b -> s gamma and bbar -> sbar gamma decays. This asymmetry is expected to be less than 0.01 in the Standard Model, but could be enhanced up to about 0.10 by new physics contributi ons. We use a sample of 89 million BB pairs recorded with the BaBar detector at PEP-II, from which we reconstruct a set of 12 exclusive b -> s gamma final states containing one charged or neutral kaon and one to three pions. We measure an asymmetry of A_CP(b -> s gamma) = 0.025 +/- 0.050(stat.) +/- 0.015(syst.), corresponding to an allowed range of -0.06 < A_CP(b -> s gamma) < +0.11 at 90% confidence level.
A measurement of $CP$-violating observables is performed using the decays $B^pmto D K^pm$ and $B^pmto D pi^pm$, where the $D$ meson is reconstructed in one of the self-conjugate three-body final states $K_{mathrm S}pi^+pi^-$ and $K_{mathrm S}K^+K^-$ (commonly denoted $K_{mathrm S} h^+h^-$). The decays are analysed in bins of the $D$-decay phase space, leading to a measurement that is independent of the modelling of the $D$-decay amplitude. The observables are interpreted in terms of the CKM angle $gamma$. Using a data sample corresponding to an integrated luminosity of $9,text{fb}^{-1}$ collected in proton-proton collisions at centre-of-mass energies of $7$, $8$, and $13,text{TeV}$ with the LHCb experiment, $gamma$ is measured to be $left(68.7^{+5.2}_{-5.1}right)^circ$. The hadronic parameters $r_B^{DK}$, $r_B^{Dpi}$, $delta_B^{DK}$, and $delta_B^{Dpi}$, which are the ratios and strong-phase differences of the suppressed and favoured $B^pm$ decays, are also reported.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا