Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userObservation of a near-threshold structure in the $K^+$ recoil-mass spectra in $e^+e^-to K^+ (D_s^- D^{*0} + D^{*-}_s D^0)$
87
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
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.
rate research
Read More
Using 1.8 million DDbar pairs and a neutrino reconstruction technique, we have studied the decays D^0 -> K^- e^+ nu_e, D^0 -> pi^- e^+ nu_e, D^+ -> Kbar^0 e^+ nu_e, and D^+ -> pi^0 e^+ nu_e. We find B(D^0 -> pi^- e^+ nu_e) = 0.299(11)(9)%, B(D^+ -> pi^0 e^+ nu_e) = 0.373(22)(13)%, B(D^0 -> K^- e^+ nu_e) = 3.56(3)(9)%, and B(D^+ -> Kbar^0 e^+ nu_e) = 8.53(13)(23)%. In addition, form factors are studied through fits to the partial branching fractions obtained in five q^2 ranges. By combining our results with recent unquenched lattice calculations, we obtain |Vcd| = 0.217(9)(4)(23) and |Vcs| = 1.015(10)(11)(106).
Using a sample of 1.8 million DDbar meson pairs collected at the psi(3770) with the CLEO-c detector, we study the semileptonic decays D^0 -> pi^- e^+ nu_e, D^+ -> pi^0 e^+ u_e, D^0 -> K^- e^+ u_e, and D^+ -> Kbar^0 e^+ nu_e. For the total branching fractions we find B(D^0 -> pi^- e^+ u_e) = 0.299(11)(9)%, B(D^+ -> pi^0 e^+ u_e) = 0.373(22)(13)%, B(D^0 -> K^- e^+ nu_e) = 3.56(3)(9)%, and B(D^+ -> Kbar^0 e^+ nu_e) = 8.53(13)(23)%, where the first error is statistical and the second systematic. In addition, form factors are studied through fits to the partial branching fractions obtained in five q^2 ranges. By combining our results with recent unquenched lattice calculations, we obtain |Vcd| = 0.217(9)(4)(23) and |Vcs| = 1.015(10)(11)(106), where the final error is theoretical.
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.
Studies of $e^+e^- to D_s^+ overline{D}{}^{(*)0}K^-$ and the $P$-wave charmed-strange mesons are performed based on an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected with the BESIII detector at $sqrt{s}= 4.600$ GeV. The processes of $e^+e^-to D_s^+ overline{D}{*}^{0} K^-$ and $D_s^+ overline{D}{}^{0} K^-$ are observed for the first time and are found to be dominated by the modes $D_s^+ D_{s1}(2536)^-$ and $D_s^+ D^*_{s2}(2573)^-$, respectively. The Born cross sections are measured to be $sigma^{B}(e^+e^-to D_s^+ overline{D}{*}^{0} K^-) = (10.1pm2.3pm0.8) pb$ and $sigma^{B}(e^+e^-to D_s^+ overline{D}{}^{0} K^-) = (19.4pm2.3pm1.6) pb$, and the products of Born cross section and the decay branching fraction are measured to be $sigma^{B}(e^+e^-to D_s^+D_{s1}(2536)^- + c.c.)cdotmathcal{B}(D_{s1}(2536)^- to overline{D}{*}^{0} K^-) = (7.5 pm 1.8 pm 0.7) pb$ and $sigma^{B}(e^+e^-to D_s^+ D^*_{s2}(2573)^- + c.c.)cdotmathcal{B}(D^*_{s2}(2573)^- to overline{D}{}^{0} K^-) = (19.7 pm 2.9 pm 2.0) pb$. For the $D_{s1}(2536)^-$ and $D^*_{s2}(2573)^-$ mesons, the masses and widths are measured to be $M(D_{s1}(2536)^-) = (2537.7 pm 0.5 pm 3.1)~MeV/c^2,$ $ Gamma(D_{s1}(2536)^-)) = (1.7pm 1.2 pm 0.6)~rm MeV,$ and $M(D^*_{s2}(2573)^-) = (2570.7pm 2.0 pm 1.7)~MeV/c^2,$ $Gamma(D^*_{s2}(2573)^-) = (17.2 pm 3.6 pm 1.1)~rm MeV.$ The spin-parity of the $D^*_{s2}(2573)^-$ meson is determined to be $J^P=2^{+}$. In addition, the process $e^+e^-to D_s^+ overline{D}{}^{(*)0} K^-$ are searched for using the data samples taken at four (two) center-of-mass energies between 4.416 (4.527) and 4.575 GeV, and upper limits at the $90%$ confidence level on the cross sections are determined.
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 $Z_{c}(3885)^{0}to Dbar{D}^*$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
