ترغب بنشر مسار تعليمي؟ اضغط هنا

Study of Excited $Xi_c$ States Decaying into $Xi_c^0$ and $Xi_c^+$ Baryons

82   0   0.0 ( 0 )
 نشر من قبل John M. Yelton
 تاريخ النشر 2016
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

Using a data sample of 980 ${rm fb}^{-1}$ of $e^+e^-$ annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we report the results of a study of excited $Xi_c$ states that decay, via the emission of photons and/or charged pions, into $Xi_c^0$ or $Xi_c^+$ ground state charmed-strange baryons. We present new measurements of the masses of all members of the $Xi_c^{prime}$, $Xi_c(2645)$, $Xi_c(2790)$, $Xi_c(2815)$, and $Xi_c(2980)$ isodoublets, measurements of the intrinsic widths of those that decay strongly, and evidence of previously unknown transitions.



قيم البحث

اقرأ أيضاً

The $Lambda_c^+K^-$ mass spectrum is studied with a data sample of $pp$ collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 fb$^{-1}$ collected by the LHCb experiment. Three $Xi_c^0$ states are observed wi th a large significance and their masses and natural widths are measured to be begin{eqnarray*} m(Xi_c(2923)^0)&=& 2923.04 pm 0.25 pm 0.20 pm 0.14 ~mathrm{MeV}, Gamma(Xi_c(2923)^0) &=& 7.1 pm 0.8 pm 1.8 ~mathrm{MeV}, end{eqnarray*} begin{eqnarray*} m(Xi_c(2939)^0) &=& 2938.55 pm 0.21 pm 0.17 pm 0.14 ~mathrm{ MeV}, Gamma(Xi_c(2939)^0) &=& 10.2 pm 0.8 pm 1.1 ~mathrm{ MeV}, end{eqnarray*} begin{eqnarray*} m(Xi_c(2965)^0) &=& 2964.88 pm 0.26 pm 0.14 pm 0.14~mathrm{ MeV}, Gamma(Xi_c(2965)^0) &=& 14.1 pm 0.9 pm 1.3~mathrm{ MeV}, end{eqnarray*} where the uncertainties are statistical, systematic, and due to the limited knowledge of the $Lambda_c^+$ mass. The $Xi_c(2923)^0$ and $Xi_c(2939)^0$ baryons are new states. The $Xi_c(2965)^0$ state is in the vicinity of the known $Xi_c(2970)^0$ baryon; however, their masses and natural widths differ significantly.
Using 980 $fb^-1$ of data collected with the Belle detector operating at the KEKB asymmetric-energy e^+e^- collider, we report a study of the electromagnetic decays of excited {charmed baryons} $Xi_c(2790)$ and $Xi_c(2815)$. A clear signal (8.6 stand ard deviations) is observed for $Xi_c(2815)^0 to Xi_c^0gamma$, and we measure: $B[Xi_c(2815)^0 to Xi_c^0gamma]/B[Xi_c(2815)^0 to Xi_c(2645)^+pi^- to Xi_c^0pi^+pi^-] = 0.41 pm 0.05 pm 0.03$. We also present evidence (3.8 standard deviations) for the similar decay of the $Xi_c(2790)^0$ and measure: $B[Xi_c(2790)^{0}toXi_c^{0}gamma]/B[Xi_c(2790)^0toXi_c^{prime +}pi^{-}toXi_c^{+}gamma pi^-] = 0.13 pm 0.03 pm 0.02$. The first quoted uncertainties are statistical and the second systematic. We find no hint of the analogous decays of the $Xi_c(2815)^+$ and $Xi_c(2790)^+$ baryons and set upper limits at the 90% confidence level of: $B[Xi_c(2815)^{+}toXi_c^{+}gamma]/B[Xi_c(2815)^+toXi_c(2645)^0pi^+toXi_c^+pi^-pi^+] < 0.09,$ and $B[Xi_c(2790)^{+}toXi_c^{+}gamma]/B[Xi_c(2790)^+toXi_c^{prime 0}pi^{+}toXi_c^{0}gamma pi^+] < 0.06.$ Approximate values of the partial widths of the decays are extracted, which can be used to discriminate between models of the underlying quark structure of these excited states.
132 - CLEO collaboration 2000
Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we report preliminary evidence for two new charmed baryons; one decaying into Xi_c^{0prime} pi^+ with the subsequent decay Xi_c^{0prime} to Xi_c^0 gamma, and its isospin partner decayi ng into Xi_c^{+prime} pi^- followed by Xi_c^{+prime} to Xi_c^+ gamma. We measure the following mass differences for the two states: M(Xi_c^0 gamma pi^+)-M(Xi_c^0)=318.4+-1.5+-2.9 MeV, and M(Xi_c^+ gamma pi^-)-M(Xi_c^+)=323.9+-pm1.4+-pm3.0 MeV. We interpret these new states as the J^P = (1/2)^-1 Xi_{c1} particles, the charmed-strange analogues of the Lambda_{c1}^+(2593).
We report measurements of the lifetimes of the $Lambda_c^+$, $Xi_c^+$ and $Xi_c^0$ charm baryons using proton-proton collision data at center-of-mass energies of 7 and 8tev, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment. The charm baryons are reconstructed through the decays $Lambda_c^+to pK^-pi^+$, $Xi_c^+to pK^-pi^+$ and $Xi_c^0to pK^-K^-pi^+$, and originate from semimuonic decays of beauty baryons. The lifetimes are measured relative to that of the $D^+$ meson, and are determined to be begin{align*} tau_{Lambda_c^+} &= 203.5pm1.0pm1.3pm1.4~{rm fs}, ewline tau_{Xi_c^+} &= 456.8pm3.5pm2.9pm3.1~{rm fs}, ewline tau_{Xi_c^0} &= 154.5pm1.7pm1.6pm1.0~{rm fs}, end{align*} where the uncertainties are statistical, systematic, and due to the uncertainty in the $D^+$ lifetime. The measurements are approximately 3--4 times more precise than the current world average values. The $Lambda_c^+$ and $Xi_c^+$ lifetimes are in agreement with previous measurements; however, the $Xi_c^0$ baryon lifetime is approximately 3.3 standard deviations larger than the world average value.
The $Xi_c^+ K^-$ mass spectrum is studied with a sample of $pp$ collision data corresponding to an integrated luminosity of 3.3 fb$^{-1}$, collected by the LHCb experiment. The $Xi_c^+$ is reconstructed in the decay mode $p K^- pi^+$. Five new, narro w excited $Omega_c^0$ states are observed: the $Omega_c(3000)^0$, $Omega_c(3050)^0$, $Omega_c(3066)^0$, $Omega_c(3090)^0$, and $Omega_c(3119)^0$. Measurements of their masses and widths are 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