0000000000948069
AUTHOR
X. L. Zhu
Observation of the $\psi(1^3D_2)$ state in $e^+e^-\to\pi^+\pi^-\gamma\chi_{c1}$ at BESIII
We report the observation of the $X(3823)$ in the process $e^+e^-\to \pi^+\pi^-X(3823) \to \pi^+\pi^-\gamma\chi_{c1}$ with a statistical significance of $6.2\sigma$, in data samples at center-of-mass energies $\sqrt{s}=$4.230, 4.260, 4.360, 4.420 and 4.600~GeV collected with the BESIII detector at the BEPCII electron positron collider. The measured mass of the $X(3823)$ is $(3821.7\pm 1.3\pm 0.7)$~MeV/$c^2$, where the first error is statistical and the second systematic, and the width is less than $16$~MeV at the 90\% confidence level. The products of the Born cross sections for $e^+e^-\to \pi^+\pi^-X(3823)$ and the branching ratio $\mathcal{B}[X(3823)\to \gamma\chi_{c1,c2}]$ are also measu…
Search forηandη′invisible decays inJ/ψ→ϕηandϕη′
Using a sample of (225.3 +/- 2.8) x 10(6) J/psi decays collected with the BESIII detector at BEPCII, searches for invisible decays of eta and eta ' in J/psi -> phi eta and phi eta ' are performed. Decays of phi -> K+K- are used to tag the eta and eta ' decays. No signals above background are found for the invisible decays, and upper limits at the 90% confidence level are determined to be 2.6 x 10(-4) for the ratio B(eta -> invisible)/B(eta ->gamma gamma) and 2.4 x 10(-2) for B(eta '-> invisible)/B(eta '->gamma gamma). These limits may be used to constrain light dark matter particles or spin-1 U bosons. DOI: 10.1103/PhysRevD.87.012009
Partial wave analysis of $\psi(2S) \to p \bar{p}\eta$
Using a sample of $1.06 \times 10^{8}$ $\psi(2S)$ events collected with the BESIII detector at BEPCII, the decay $\psi(2S) \to p \bar{p}\eta$ is studied. A partial wave analysis determines that the intermediate state N(1535) with a mass of $1524\pm5^{+10}_{-4}$ MeV/$c^2$ and a width of $130^{+27+57}_{-24-10}$ MeV/$c^2$ is dominant in the decay; the product branching fraction is determined to be $B(\psi(2S) \to N(1535)\bar{p})\times B(N(1535)\to p\eta)+c.c. = (5.2\pm0.3^{+3.2}_{-1.2})\times 10^{-5}$. Furthermore, the branching fraction of $\psi(2S) \to \eta p \bar{p}$ is measured to be $(6.4\pm0.2\pm0.6)\times 10^{-5}$.
Precise Measurement of the e(+)e(-) ->pi(+)pi(-) J/psi Cross Section at Center-of-Mass Energies from 3.77 to 4.60 GeV
The cross section for the process e(+)e(-)-> pi(+) pi(-) J/psi is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb(-1) of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (222.0 +/- 3.1 +/- 1.4) MeV/ c(2) and a width of (44.1 +/- 4.3 +/- 2.0)MeV, while the second one has a mass of (4320.0 +/- 10.4 +/- 7.0)MeV/c(2) and a width of (101.4(- 19.7)(+25.3) +/- 10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The prec…
Observation of the decayψ(3686)→ΛΣ¯±π∓+c.c.
Using a sample of 1:06 X 10(8) psi(3686) events collected with the BESIII detector, we present the first observation of the decays of psi(3686) -> Lambda(Sigma) over bar (+) pi(-) + c.c. and psi(3686) -> Lambda(Sigma) over bar (-) pi(+) + c.c. The branching fractions are measured to be B(psi(3686) -> Lambda(Sigma) over bar (+) pi(-) + c.c.) = (1.40 +/- 0.03 +/- 0.13) X 10(-4) and B(psi(3686) -> Lambda (Sigma) over bar (-) pi(+) + c.c.) = (1.54 +/- 0.04 +/- 0.13) X 10(-4) where the first errors are statistical and the second ones systematic.
Measurement of the integrated luminosities of the data taken by BESIII at √ s = 3.650 and 3.773 GeV
Data sets were collected with the BESIII detector at the BEPC II collider at the center-of-mass energy of root s=3.650 GeV during May 2009 and at root s=3.773 GeV from January 2010 to May 2011. By analyzing the large angle Bhabha scattering events, the integrated luminosities of the two data sets are measured to be (44.49 +/- 0.02 +/- 0.44) pb(-1) and (2916.94 +/- 0.18 +/- 29.17) pb(-1), respectively, where the first error is statistical and the second error is systematic.
Observation of the Leptonic Decay $D^+ → τ^+ ν_τ$
Physical review letters 123(21), 211802 (2019). doi:10.1103/PhysRevLett.123.211802
Evidence for $\eta_{c} \rightarrow \gamma\gamma$ and Measurement of $J/\psi\rightarrow 3\gamma$
The decay of $J/\psi$ to three photons is studied using $\psi(3686)\to\pi^+\pi^-J/\psi$ in a sample of $1.0641\times10^8$ $\psi(3686)$ events collected with the BESIII detector. Evidence of the direct decay of $\eta_c$ to two photons, $\eta_c\to\gamma\gamma$, is reported, and the product branching fraction is determined to be $\mathcal{B}(J/\psi\to\gamma\eta_c,\eta_c\to \gamma\gamma)=(4.5\pm1.2\pm0.6)\times10^{-6}$, where the first error is statistical and the second is systematic. The branching fraction for $J/\psi\to3\gamma$ is measured to be $(11.3\pm1.8\pm2.0)\times 10^{-6}$ with improved precision.
Study of Open-Charm Decays and Radiative Transitions of the X(3872)
The processes X(3872)→D*0D¯0+c.c.,γJ/ψ,γψ(2S), and γD+D− are searched for in a 9.0 fb−1 data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe X(3872)→D*0D0¯+c.c. and find evidence for X(3872)→γJ/ψ with statistical significances of 7.4σ and 3.5σ, respectively. No evident signals for X(3872)→γψ(2S) and γD+D− are found, and the upper limit on the relative branching ratio Rγψ≡{B[X(3872)→γψ(2S)]}/{B[X(3872)→γJ/ψ]}<0.59 is set at 90% confidence level. Measurements of branching ratios relative to decay X(3872)→π+π−J/ψ are also reported for decays X(3872)→D*0D0¯+c.c.,γψ(2S),γJ/ψ, and γD+D−, as well as the non-D*0D0¯ three-body decays π0…
Measurement of the Absolute Branching Fraction of the Inclusive Decay Λc+ → Λ+X
Physical review letters 121(6), 062003 (2018). doi:10.1103/PhysRevLett.121.062003
Measurements of absolute hadronic branching fractions of the Λc+ baryon
Kolcu, Onur Buğra (Arel Author) --- Makale 69 yazarlıdır.
Search for Baryonic Decays of \psi(3770) and \psi(4040)
By analyzing data samples of 2.9 fb^{-1} collected at \sqrt s=3.773 GeV, 482 pb^{-1} collected at \sqrt s=4.009 GeV and 67 pb^{-1} collected at \sqrt s=3.542, 3.554, 3.561, 3.600 and 3.650 GeV with the BESIII detector at the BEPCII storage ring, we search for \psi(3770) and \psi(4040) decay to baryonic final states, including \Lambda\bar\Lambda\pi^+\pi^-, \Lambda \bar\Lambda\pi^0, \Lambda\bar\Lambda\eta, \Sigma^+ \bar\Sigma^-, \Sigma^0 \bar\Sigma^0, \Xi^-\bar\Xi^+ and \Xi^0\bar\Xi^0 decays. None are observed, and upper limits are set at the 90% confidence level.
Search for $\eta$ and $\eta^\prime\to \pi^+ e^- \bar{\nu}_e +c.c.$ decays in $\jpsi \to \phi \eta$ and $\phi \eta^\prime$
Using a sample of 225.3 million $\jpsi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider in 2009, searches for the decays of $\eta$ and $\eta^\prime\to\pi^+ e^- \bar{\nu}_e +c.c.$ in $\jpsi \to \phi \eta$ and $\phi\eta^\prime$ are performed. The $\phi$ signals, which are reconstructed in $K^+K^-$ final states, are used to tag $\eta$ and $\eta^\prime$ semileptonic decays. No signals are observed for either $\eta$ or $\eta^\prime$, and upper limits at the 90% confidence level are determined to be $7.3\times 10^{-4}$ and $5.0\times 10^{-4}$ for the ratios $\frac{{\mathcal B}(\eta\to \pi^+ e^- \bar{\nu}_e +c.c.)}{{\mathcal B}(\eta \to \pip\pim\piz)}$ and $\frac{{\mathca…
Dark photon search in the mass range between 1.5 and 3.4 GeV/c2
Physics letters / B 774, 252 - 257 (2017). doi:10.1016/j.physletb.2017.09.067
Measurement of $\eta^\prime\rightarrow \pi^+\pi^- e^+e^-$ and $\eta^\prime\rightarrow \pi^+\pi^-\mu^+\mu^-$
Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum, and the branching fraction is measured to be \BR(\eta' to pi+pi-e+e-) = (2.11\pm0.12 (stat.)\pm0.15 (syst.))\times10^{-3}, which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No \eta' signal is found in the pi+ pi- mu+ mu- mass spectrum, and the upper limit is determined to be \BR(\eta' to pi+ pi- mu+ mu-)<2.9\times10^{-5} at the 90% confidence level.
Observation of a cross-section enhancement near mass threshold in e + e - → Λ Λ
The process e(+)e(-) -> Lambda(Lambda) over bar is studied using data samples at root s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. The Born cross section is measured at root s = 2.2324 GeV, which is 1.0 MeVabove the Lambda(Lambda) over bar mass threshold, to be 305 +/- 45(-36)(+66) pb, where the first uncertainty is statistical and the second systematic. The cross section near threshold is larger than that expected from theory, which predicts the cross section to vanish at threshold. The Born cross sections at root s = 2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with…
Amplitude analysis and branching fraction measurement of Ds+→K−K+π+π0
We report an amplitude analysis and branching fraction measurement of Ds+→K+K−π+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV. We perform a model-independent partial wave analysis in the low K+K− mass region to determine the K+K− S-wave line shape, followed by an amplitude analysis of our very pure high-statistics sample. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(Ds+→K+K−π+)=(5.47±0.08stat±0.13sys)%.
Search for $\eta$ and $\eta'$ Invisible Decays in $J/\psi\to\phi\eta$ and $\phi\eta'$
Using a sample of $(225.3\pm 2.8)\times 10^{6}$ $J/\psi$ decays collected with the BESIII detector at BEPCII, searches for invisible decays of $\eta$ and $\eta^\prime$ in $J/\psi\to\phi\eta$ and $\phi\eta^\prime$ are performed. Decays of $\phi \to K^{+}K^{-}$ are used to tag the $\eta$ and $\eta^\prime$ decays. No signals above background are found for the invisible decays, and upper limits at the 90% confidence level are determined to be $2.58\times10^{-4}$ for the ratio $\frac{\mathcal{B}(\eta\to\rm{invisible})}{\mathcal{B}(\eta\to\gamma\gamma)}$ and $2.39\times10^{-2}$ for $\frac{\mathcal{B}(\eta^\prime\to\rm{invisible})}{\mathcal{B}(\eta^\prime \to\gamma\gamma)}$.
Two-photon widths of the $\chi_{c0, 2}$ states and helicity analysis for $\chi_{c2}\ar\gamma\gamma$}
Based on a data sample of 106 M $\psi^{\prime}$ events collected with the BESIII detector, the decays $\psi^{\prime}\ar\gamma\chi_{c0, 2}$,$\chi_{c0, 2}\ar\gamma\gamma$ are studied to determine the two-photon widths of the $\chi_{c0, 2}$ states. The two-photon decay branching fractions are determined to be ${\cal B}(\chi_{c0}\ar\gamma\gamma) = (2.24\pm 0.19\pm 0.12\pm 0.08)\times 10^{-4}$ and ${\cal B}(\chi_{c2}\ar\gamma\gamma) = (3.21\pm 0.18\pm 0.17\pm 0.13)\times 10^{-4}$. From these, the two-photon widths are determined to be $\Gamma_{\gamma \gamma}(\chi_{c0}) = (2.33\pm0.20\pm0.13\pm0.17)$ keV, $\Gamma_{\gamma \gamma}(\chi_{c2}) = (0.63\pm0.04\pm0.04\pm0.04)$ keV, and $\cal R$ $=\Gamma…
Measurement of the absolute branching fraction of the inclusive semileptonic $\Lambda_c^+$ decay
Physical review letters 121(25), 251801 (2018). doi:10.1103/PhysRevLett.121.251801
First observation of the isospin violating decay $J/\psi\rightarrow \Lambda\bar{\Sigma}^{0}+c.c.$
Using a sample of $(225.2\pm 2.8)\times 10^6$ $J/\psi$ events collected with the BESIII detector, we present results of a study of $J/\psi\rightarrow \gamma\Lambda\bar{\Lambda}$ and report the first observation of the isospin violating decay $J/\psi\rightarrow\Lambda\bar{\Sigma}^{0}+c.c.$, in which $\bar{\Sigma}^{0}$ decays to $\gamma \bar{\Lambda}$. The measured branching fractions are $\mathcal{B}(J/\psi\rightarrow\bar{\Lambda}\Sigma^{0}$) = $(1.46\pm0.11\pm0.12) \times10^{-5}$ and $\mathcal{B}(J/\psi\rightarrow\Lambda\bar{\Sigma^{0}}$) = $(1.37\pm0.12\pm0.11) \times10^{-5}$. We search for $\Lambda(1520) \rightarrow \gamma \Lambda$ decay, and find no evident signal, and an upper limit for…
Measurement of the phase between strong and electromagnetic amplitudes of J/ψ decays
Kolcu, Onur Buğra (Arel Author)
Evidence for the Direct Two-Photon Transition from $\psi(3686)$ to $J/\psi$
The two-photon transition $\psi(3686)\to\gamma\gamma J/\psi$ is studied in a sample of 106 million $\psi(3686)$ decays collected by the BESIII detector. The branching fraction is measured to be $(3.1\pm0.6(\unit{stat})^{+0.8}_{-1.0}(\unit{syst})) \times10^{-4}$ using $J/\psi\to e^+e^-$ and $J/\psi\to\mu^+\mu^-$ decays, and its upper limit is estimated to be $4.5\times10^{-4}$ at the 90% conference level. This work represents the first measurement of a two-photon transition among charmonium states. The orientation of the $\psi(3686)$ decay plane and the $J/\psi$ polarization in this decay are also studied. In addition, the product branching fractions of sequential $E1$ transitions $\psi(3686…