Do you want to publish a course? Click here

Observation of a Neutral Structure near the $Dbar{D}^{*}$ Mass Threshold in $e^{+}e^{-}to (D bar{D}^*)^0pi^0$ at $sqrt{s}$ = 4.226 and 4.257 GeV

90   0   0.0 ( 0 )
 Added by Wei Shan
 Publication date 2015
  fields
and research's language is English




Ask ChatGPT about the research

A neutral structure in the $Dbar{D}^{*}$ system around the $Dbar{D}^{*}$ mass threshold is observed with a statistical significance greater than 10$sigma$ in the processes $e^{+}e^{-}rightarrow D^{+}D^{*-}pi^{0}+c.c.$ and $e^{+}e^{-}rightarrow D^{0}bar{D}^{*0}pi^{0}+c.c.$ at $sqrt{s}$ = 4.226 and 4.257 GeV in the BESIII experiment. The structure is denoted as $Z_{c}(3885)^{0}$. Assuming the presence of a resonance, its pole mass and width are determined to be ($3885.7^{+4.3}_{-5.7}$(stat)$pm 8.4$(syst)) MeV/$c^{2}$ and ($35^{+11}_{-12}$(stat)$ pm 15$(syst)) MeV, respectively. The Born cross sections are measured to be $sigma(e^{+}e^{-}to Z_{c}(3885)^{0}pi^{0}, Z_{c}(3885)^{0} to Dbar{D}^{*})=(77 pm 13$(stat)$pm 17$(syst)) pb at 4.226 GeV and ($47 pm 9$(stat)$ pm 10$(syst)) pb at 4.257 GeV. The ratio of decay rates $frac{mathcal{B}({Z_{c}(3885)^{0} to D^{+}D^{*-}+c.c.})}{mathcal{B}({Z_{c}(3885)^{0} to D^{0}bar{D}^{*0}+c.c.})}$ is determined to be $0.96 pm 0.18$(stat)$pm 0.12$(syst), consistent with no isospin violation in the process $Z_{c}(3885)^{0}to Dbar{D}^*$.



rate research

Read More

We study the process $e^+e^- to (D^{*} bar{D}^{*})^{pm} pi^mp$ at a center-of-mass energy of 4.26GeV using a 827pb$^{-1}$ data sample obtained with the BESIII detector at the Beijing Electron Positron Collider. Based on a partial reconstruction technique, the Born cross section is measured to be $(137pm9pm15)$pb. We observe a structure near the $(D^{*} bar{D}^{*})^{pm}$ threshold in the $pi^mp$ recoil mass spectrum, which we denote as the $Z^{pm}_c(4025)$. The measured mass and width of the structure are $(4026.3pm2.6pm3.7)$MeV/c$^2$ and $(24.8pm5.6pm7.7)$MeV, respectively. Its production ratio $frac{sigma(e^+e^-to Z^{pm}_c(4025)pi^mp to (D^{*} bar{D}^{*})^{pm} pi^mp)}{sigma(e^+e^-to (D^{*} bar{D}^{*})^{pm} pi^mp)}$ is determined to be $0.65pm0.09pm0.06$. The first uncertainties are statistical and the second are systematic.
We report a study of the processes of $e^+e^-to K^+ (D_s^- D^{*0} + D^{*-}_s D^0)$ based on $e^+e^-$ annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb$^{-1}$. An excess over the known contributions of the conventional charmed mesons is observed near the $D_s^- D^{*0}$ and $D^{*-}_s D^0$ mass thresholds in the $K^{+}$ recoil-mass spectrum for events collected at $sqrt{s}=4.681$ GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as $(3982.5^{+1.8}_{-2.6}pm2.1)$ MeV/$c^2$ and $(12.8^{+5.3}_{-4.4}pm3.0)$ MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 $sigma$ over the contributions only from the conventional charmed mesons. This is the first candidate of the charged hidden-charm tetraquark with strangeness, decaying into $D_s^- D^{*0}$ and $D^{*-}_s D^0$. However, the properties of the excess need further exploration with more statistics.
We report a study of the process $e^{+} e^{-} to (D^{*} bar{D}^{*})^{0} pi^0$ using $e^+e^-$ collision data samples with integrated luminosities of $1092 rm{pb}^{-1}$ at $sqrt{s}=4.23 rm{GeV}$ and $826 rm{pb}^{-1}$ at $sqrt{s}=4.26 rm{GeV}$ collected with the BESIII detector at the BEPCII storage ring. We observe a new neutral structure near the $(D^{*} bar{D}^{*})^{0}$ mass threshold in the $pi^0$ recoil mass spectrum, which we denote as $Z_{c}(4025)^{0}$. Assuming a Breit-Wigner line shape, its pole mass and pole width are determined to be $(4025.5^{+2.0}_{-4.7}pm3.1) rm{MeV}/c^2$ and $(23.0pm 6.0pm 1.0) rm{MeV}$, respectively. The Born cross sections of $e^{+}e^{-}to Z_{c}(4025)^{0} pi^0to (D^{*} bar{D}^{*})^{0}pi^0$ are measured to be $(61.6pm8.2pm9.0) rm{pb}$ at $sqrt{s}=4.23 rm{GeV}$ and $(43.4pm8.0pm5.4) rm{pb}$ at $sqrt{s}=4.26 rm{GeV}$. The first uncertainties are statistical and the second are systematic.
124 - B. R. Ko , E. Won , I. Adachi 2014
We observe $D^0-bar{D}^0$ mixing in the decay $D^0rightarrow K^+pi^-$ using a data sample of integrated luminosity 976 fb$^{-1}$ collected with the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. We measure the mixing parameters ${x}^2 = (0.09pm0.22)times 10^{-3}$ and $y = (4.6pm3.4)times 10^{-3}$ and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates $R_D = (3.53pm0.13)times 10^{-3}$, where the uncertainties are statistical and systematic combined. Our measurement excludes the no-mixing hypothesis at the 5.1 standard deviation level.
We report a measurement of the parameter $y_{CP}$ in $ensuremath{D^0}xspace-ensuremath{overline{D}^{0}}xspace$ oscillations performed by taking advantage of quantum coherence between pairs of $ensuremath{D^0}xspace ensuremath{overline{D}^{0}}xspace$ mesons produced in $e^+e^-$ annihilations near threshold. In this work, doubly-tagged $ensuremath{D^0}xspace ensuremath{overline{D}^{0}}xspace$ events, where one $D$ decays to a $CP$ eigenstate and the other $D$ decays in a semileptonic mode, are reconstructed using a data sample of 2.92,fb$^{-1}$ collected with the BESIII detector at the center-of-mass energy of $sqrt{s}$ = 3.773,GeV. We obtain $y_{CP} = (-2.0pm1.3pm0.7)%$, where the first uncertainty is statistical and the second is systematic. This result is compatible with the current world average.
comments
Fetching comments Fetching comments
Sign in to be able to follow your search criteria
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا