6 pages, 2 figures. Proceedings for "The Xth Nicola Cabibbo International Conference on Heavy Quarks and Leptons, October 11-15 2010, Frascati, Rome, Italy"
Using about $226\times 10^6$ $\jpsi$ events and $106\times 10^6$ $ψ^{\prime}$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider, the Dalitz plot of $\etap \to ηπ^+ π^-$ decay is studied, the direct measurement of $a^{0}_{0}(980)-f_{0}(980)$ mixing is performed, $X(2120)$ and $X(2370)$ are observed in the $π^+π^-η^\prime$ invariant mass spectrum, $ψ^{\prime}\toγπ^0$ and $ψ^{\prime}\toγη$ are observed for the first time, and the decays $χ_{cJ}\toγV$ ($V=ϕ$, $ρ^0$, $ω$) are studied.
BESIII is a new state-of-the-art 4$π$ detector at the upgraded BEPCII two-ring $\ee$ collider at the Institute of High Energy Physics in Beijing, China. It has been in operation since 2008, and has collected the world's largest data samples of $\jpsi$, $\psip$ and $ψ(3770)$ decays, as well as $τ$ mass scan and low energy points for $R$ measurement. These data are being used to make a variety of interesting and unique studies of light-hadron spectroscopy, precision charmonium physics, high-statistics measurements of $D$ meson decays, $τ$ mass measurement and $R$ measurement. Results summarized …
In 2009, the BESIII experiment has collected about 225M $\jpsi$ and 106M $\psip$ samples, both of which are the world largest on-peak charmonium production. Based on these dataset, BESIII has made great effort on the study of the charmonium decays, some important of which have been reviewed in this proceeding. In addition, a searching for new physics through the $CP/P$ violation process is reported.
The Dalitz plot of $η^{\prime} \to ηπ^+ π^-$ decay is studied using $(225.2\pm2.8)\times 10^6$ $\jpsi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider. With the largest sample of $η^{\prime}$ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also the branching fraction of $\jpsi \to γη^{\prime}$ is determined to be $(4.84\pm0.03\pm0.24)\times 10^{-3}$, where the first error is statistical and the second systematic.
It was argued long ago that eta_b could be observed through the eta_b => Jpsi(=> mu+ mu-) Jpsi(=> mu+ mu-) decay chain. Recent calculations indicate that the width of eta_b into two Jpsi is almost 3 orders of magnitude smaller than the one into the D bar D*. We study the effects of final-state interactions due to the D bar D* intermediate state on the Jpsi Jpsi final state. We find that the inclusion of this contribution may enhance the short-distance branching ratio up to about 2 orders of magnitude.
多夸克搜索是近年来的一个热门话题。在对北京谱仪Ⅱ探测器收集的58 M $\jpsi$事例进行分析的过程中，观察到了一些阈值增强现象。这些增强不能用标准模型解释，可能是多夸克的候选者。北京谱仪对轻标量介子的研究也有很大贡献，如$σ$、$κ$、$f_{0}(1370)$和$f_{0}(1710)$等。利用北京谱仪的$\jpsi$事件，还进行了重子激发态的研究和$\jpsi$衰变的测量。
A brief report of some recent experimental developments concerning the $X$, $Y$ and $Z$ charmoniumlike mesons states and other puzzling states from the BaBar, Belle, BESIII and CDF experiments is presented.
The BESIII experiment has collected world's largest direct $e^+e^-$ colliding beam data at the $J/ψ$, $ψ'$, $ψ$(3770) and at and around the $Y$(4260). These data have enabled the study of hadrons at unprecedented precisions. We present results on the light hadron spectroscopy, production of hadrons in radiative decays of charmonia, observation of new excited $N^*$ baryons and of anomalous decays of the $η/η'$ states.
About 2.9 fb$^{-1}$ data set had been collected with the BESIII detector at the BEPCII collider. Taking advantages of data near open-charm threshold, we present preliminary results on leptonic and semileptonic charm-meson decays, as well as result on the FCNC process $D^0 \rightarrow γγ$ from BESIII experiment. High precision charm data will enable us to validate Lattice QCD calculations at the few percent level. These can then be used to make precise measurements of CKM elements, $V_{cd}$ and $V_{cs}$, which are useful to improve the accuracy of test of the CKM unitary.
This report highlights the recent BESIII results related to the measurement of the $R$ value, radiative decays of $J/ψ$ and the polarization of $D^0 \to ωϕ$ decay. BESIII, a symmetric electron-positron collider experiment, has collected a large data sample at several energy points in the tau-charm region, including the $J/ψ$ and $ψ(3770)$ resonances. Based on the data samples collected at 14 center-of-mass energy ($\sqrt{s}$) points between 2.2323 and 3.671 GeV, BESIII has achieved a measurement of the $R$ value with an accuracy down to the level of $2.6\%$ for $\sqrt{s} < 3.1$ GeV and $3.0\%$…
We present the most recent results from the BESIII experiment. This review covers the studies of charmonium decays, light hadron spectroscopy and charm physics. Especially, the prospects for weak decays of charm mesons are addressed at the BESIII.
Charmonium spectroscopy provides strong guidelines to effective field theories, thereby gaining insight into quark confinement and the generation of hadron masses. Hadronic transitions between charmonium states have been measured with unprecedented high precision with the BESIII spectrometer at IHEP Beijing, China. We present systematic studies of isospin-violating decays in charmonium, such as $ψ' \rightarrow π^{0} J/ψ$, $ψ' \rightarrow π^{0} h_{c}$, $e^{+}e^{-} \rightarrow π^{0} J/ψ$ at $\sqrt{s}=$ 4.009 GeV, and their improved measurements of their branching fractions.
Using a sample of $(225.2\pm 2.8)\times 10^6$ $J/ψ$ events collected with the Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider, CP and $P$ violating decays of $η$, $η'$ and $\etac$ into $π^+π^-$ and $π^0 π^0$ are searched for in $\jpsi$ radiative decays. No significant $η$, $η'$ or $\etac$ signal is observed, and 90% confidence level upper limits of $\BR(η\to π^+π^-)<3.9\times 10^{-4}$, $\BR(η' \to π^+π^-)<5.5\times 10^{-5}$, $\BR(\etac \to π^+π^-)<1.3\times 10^{-4}$, $\BR(η\to π^0 π^0)<6.9\times 10^{-4}$, $\BR(η' \to π^0 π^0)<4.5\times 10^{-4}$ and $\BR(\etac \to π^0 π^…
We review three recent results of the CDF collaboration on Bs suppressed decays: the first search for CP--violation in the Bs-->phi phi decay, where two CP--violating asymmetries expected to be zero in the Standard Model are measured, and the observation and the branching ratio measurements of Bs-->jpsi fnot and Bs-->jpsi K(*) decays.
Studies of light meson decays are important tools to perform precision tests of the effective field theories, determine transition form factors, and test fundamental symmetries. With very high statistics data samples, the BESIII experiment provides a unique laboratory for light meson studies and is contributing significantly to a variety of these investigations. A brief review of recent progress in light meson decay studied at the BESIII experiment, including detailed studies of common decay dynamics, searches for rare/forbidden decays and new particles, is presented. Finally, together with de…
Hadron spectroscopy is one of the most important physics goals of BESIII. BESIII brings great opportunities to study the XYZ states of charmonium by directly producing the Y states up to 4.6 GeV. High statistics of charmonium decays collected at BESIII provide an excellent place for hunting gluonic excitations and studying the excited baryons. Recent results of light hadron spectroscopy and charmonium spectroscopy from BESIII will be reported.
BESIII experiment has collected about 20 fb$^{-1}$ luminosity data between $\sqrt{s}=3.8$ and 4.7 GeV via $e^{+}e^{-}$ collision. In this talk, we present the recent $XYZ$ results at BESIII, including mass and width measurements of $Y(4220)$, search for $Y$ states with rare decay modes, isospin parity determination of $Z_{c}^{0}(3900)$ as well as the mass and width determination, and search for new decay modes of $X(3872)$.
We report the latest outcomes for the Charmonium system investigation on 226x10^6 J/Psi and 106x10^6 Psi' events collected with the BESIII detector at the BEPCII e+e- collider.
With the help of the largest data samples of $J/ψ$ and $ψ(2S)$ events ever produced in $e^+e^-$ annihilations, the three singlet charmonium states, $η_c(1S)$, $η_c(2S)$ and $h_c(1P)$, have been extensively studied at the BESIII experiment. In this review, a survey on the most recent results, including a series of precision measurements and observations of their new decay modes, is presented, which indicates the further investigations on their decays are needed to understand their decay mechanisms and have precision tests of the theoretical models. At present, about eight times larger data samp…
Spin polarization and entanglement are utilized by the BESIII experiment to learn more about the production and decay properties of hyperon-antihyperon pairs in a series of recent analyses of its unprecedented datasets at the $J/ψ$ and $ψ'$ resonances. This has lead to the observation of significant transverse polarisation in decays of $J/ψ$ or $ψ'$ into $Λ\barΛ$, $Σ\barΣ$, $Ξ\barΞ$, and $Ω\barΩ$. Because of the non-zero polarization, the decay parameters for the most common hadronic weak decays of both hyperons and antihyperons could be determined independently for the first time. Comparing t…
We report some recent results on charmonium spectroscopy and hadron spectroscopy from BESIII experiment, including the measurements of the masses and widths of $h_c$, $η_c$, $η_c(2S)$ and some new resonances around 2 GeV. The results are based on a data sample of 106 million $ψ^\prime$ events and 226 million J/$ψ$ events collected with the BESIII detector at the BEPCII collider.
The recent results on Charmonium and Charmonium-like states at BESIII are reviewed, including the observation of $\rm Z_{cs}(3985)$ state, the study of the new decay modes of $ψ_2(3823)$ state, observation of resonance structure in $\rm e^+e^- \to π^+π^-ψ_2(3823)$ process, the study of the $\rm e^+e^- \to K^+K^-J/ψ$ process, cross section measurement of $\rm e^+e^- \to ωπ^0$ and $ωη$ process, branching fraction measurement of $ψ(3686)\to\barΣ^0Λ+ c.c.$ process. Decay channels for $χ_{cJ} \to Λ\barΛ$, $χ_{cJ} \to Λ\barΛη$, $ψ(3686) \to Λ\barΛω$ and $η_c(2S)\to3(π^+π^-)$ are also discussed. The …
I report BESIII preliminary results on: 1 Measurement of sigma(e+e- ->DDbar at Ecm = 3.773 GeV 2 Study of the DDbar production line shape near Ecm = 3.773 GeV 3 The first observation of singly Cabibbo-suppressed decay, D -> omega pi 4 Measurement of BF(Ds+ -> eta' X) and BF(Ds+ -> eta' rho+) .
In this talk, we present a selection of recent results from BESIII collaboration, including observation of the charmoniumlike states, Zc(3900), Zc(4020) and Zc(4025); observation of e+e- -> gamma X(3872); partial wave analysis of J/psi -> gamma eta eta; measurement of D+ -> mu+ nu and D0 -> K- e+ nu, pi- e+ nu. The results are based on the data samples collected with the BESIII detector at central-of-mass energies from 3.900 to 4.420 GeV, and at the energies of J/psi and psi(3770) resonances.
Recently, LHCb experiment announced a 3.5$σ$ evidence for direct CP violation in $D^0$ decay by looking at the difference between $A_{CP}(D^0\rightarrow K^+K^-)$ and $A_{CP}(D^0\rightarrow π^+π^-)$. This is the first evidence of CP violation in charm system, which may indicate new physics beyond the Standard Model. Motivated by this measurement, we review rare processes in charmonium decay, especially, the weak decay, $C$ or $P$ violated decay and lepton flavor violated decays. In case the new physics appears in charm sector, these rare decays of charmonium states will provide opportunity to s…
In recent years, lots of studies of charmonium decays have been performed at BESIII based on large data samples of $J/ψ$, $ψ(3686)$ and $ψ(3770)$. Recent results in searches for radiative transitions of $ψ(3770)$ and rare phenomena in charmonium decays, and studies of light hadrons structures and properties will be presented.
The BESIII experiment, based on the BEPCII collider at IHEP in Beijing, China, is capable of measuring nucleon form factors with unprecedented precision. We report recent results achieved by the BESIII collaboration concerning the nucleon time-like form factors and the hyperon pair production. More in detail we outline the results obtained by the study of the process $e^+e^- \to p \overline p$, using both the scan-energy and initial-state radiation techniques, those of the process $e^+e^- \to n \overline n$, and the study of the $Σ$ polarization regarding the process $e^+e^- \to J/ψ\to Σ^+\ove…
Despite the successes of the standard model, the non-perturbative dynamics of the strong interaction are not fully understood yet. Charmonium spectroscopy serves as an ideal tool to shed light on the dynamics of the strong interaction such as quark confinement and the generation of hadron masses. The BESIII collaboration studies extensively the strong interaction and various aspects that could shed light on physics beyond the standard model via copious e$^+$e$^-$ collisions at the BESIII/BEPCII facility in Beijing, China, in the charmonium mass regime. I present a few of the recent results wit…
Despite being extensively studied since their initial discovery in 2003, the XYZ states do not yet have a clear interpretation. BESIII recently collected additional data above 4 GeV which can be used to further study these exotic hadron candidates. We present recent studies of $X(3872)\toπ^0χ_{c0}$, $e^+e^-\to K^+K^-J/ψ$, $e^+e^-\to$ light hadrons, $e^+e^-\to D^{*+}D^{(*)-}$, and on the $Z_{cs}(3985)$.
We present recent BESIII results about the study of mesons which contain at least one charm quark. We determined the D(s)+ decay constants, the form factors of D semi-leptonic decays, the CKM matrix elements |Vcs(d)|.
With about 12 fb$^{-1}$ collected XYZ data sets, BESIII continues the exploration of the exotic charmonium-like states. In this talk, recent results on the measurements of the spin-parity determination of $Z_{\rm c}(3900)$, as well as on line-shapes of $e^+e^- \rightarrow J/ψ\,ππ, h_{\rm c}ππ, ψ(2S)\,π^0π^0/π^+π^-$, and $π^+ D^0 D^{*-}$ from open charm are discussed. Also, the recent observation of $e^+ e^- \rightarrow ϕχ_{c1/2}$ at $\sqrt(s)=4.6$ GeV is reported.
The world's largest sample of $J/ψ$ events accumulated at the BESIII dector offers a unique opportunity to investigate $η$ and $η^\prime$ physics via two body $J/ψ$ radiative or hadronic decays. In recent years the BESIII experiment has made significant progresses in $η/η^\prime$ decays. A selection of recent highlights in light meson spectroscopy at BESIII are reviewed in this report, including the observation of $η^\prime\rightarrowπ^+π^-μ^+μ^-$, the study of $η^\prime\rightarrowπ^+π^-e^+e^-$, and search for $CP$-violation in this decay, search for the rare decays of $η^\prime\rightarrow4π^0…
The recent measurement results of exotic charmonium-like states, the so called XYZ particles, at BESIII have been presented. I mainly discussed the charged Zc(3900) state, its neutral partner, and possible excited states.
Stimulated by the recent BESIII observation of a new resonance in $e^+ e^- \to ωχ_{c0}$ and by the fact that this state is consistent with our predicted $ψ(4S)$, in this work we estimate the meson loop contribution to $ψ(4S) \to ωχ_{c0}$. The evaluation indicates that our theoretical estimate can overlap with the experimental data in a reasonable parameter range. This fact shows that introduction of the missing higher charmonium $ψ(4S)$ provides a possible explanation to the recent BESIII observation. The upper limit of a branching ratio of $ψ(4S) \to ηJ/ψ$ is also predicted as $1.9 \times 10^…
Many extensions of the Standard Model introduce a new type of weak-interacting degrees of freedom. These models are motivated by the results of recent experimental anomalies. Typical models, such as Next-to-Minimal Supersymmetric Standard Model and Light Hidden Dark-sector Model, introduce the possibilities of low-mass Higgs and dark bosons. The masses of such particles are expected to be few GeV and thus making them accessible at BESIII experiment, an $e^+e^-$ collider experiment running at tau-charm region. This report summarizes the recent results of low-mass Higgs and dark bosons searches …
Charm hadronic decays are an important tool for understanding the the hadron spectroscopy and dynamics of the strong interaction in the low energy regime. BESIII experiment has collected a huge amount of data at various energy points around $D\bar{D}$ and $D_sD_s^*$ threshold. This report summarizes recent amplitude analyses and branching fraction measurements results of BESIII related to $D_{(s)}$ decays.
The latest results on chi_cJ(1P) decays from BESIII and CLEO-c are reviewed and compared to theoretical predictions. The experimental results use the final samples of chi_cJ(1P) decays from CLEO-c, obtained from 26 million psi(2S) decays, and the most recent samples from BESIII, from a starting sample of 106 million psi(2S) decays.
Light hadron spectroscopy plays an important role in understanding the decay dynamics of unconventional hadronic states, such as strangeonium and glueballs. BESIII provides an ideal avenue to search for these exotic states thanks to a huge amount of data recorded at various energy points in the tau-charm mass region including J/psi resonance. This report summarizes recent results of the BESIII experiment related to the glueballs and strangeonium-like states.
In the quark model, hadrons are dominantly bound states of quark-antiquark pairs (mesons) or three quarks (baryons), but QCD also allows hadronic states to be composed of more quarks bound together. Recently, BESIII, Belle and LHCb have confirmed the existence of four-quark and pentaquark candidates. These new states, along with experimentally observed resonances that do not fit well into the charmonium and bottomonium spectra, present challenges and opportunities for strong interaction theory. In this talk, I will review results on charmonium-like exotic quark states that have been observed b…
Using 58 million $J/ψ$ and 14 million $ψ(2S)$ events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays $J/ψ$ and $ψ(2S) \to Λ\barΛ π^0$ and $Λ\barΛ η$ are measured, and the decays of $J/ψ$ and $ψ(2S)$ to $n K^0_S \barΛ+c.c.$ are observed and measured for the first time. Finally, $R$ measurement data taken with the BESII detector at center-of-mass energies between 3.7 and 5.0 GeV are fitted to determine resonance parameters of the high mass charmonium states, $ψ(3770)$, $ψ(4040)$, $ψ(4160)$, and $ψ(4415)$. The Beijing Electron Collider is being upgr…
With about 12 fb$^{-1}$ of collected data useful for the study of $XYZ$ states, BESIII collaboration continues the exploration of these exotic charmoniumlike states. Recent results of the measurements of the line-shape of $e^+e^-\toπ^0π^0ψ(3686)$, $KKJ/ψ$, and $π^+D^0D^{*-}$, as well as the $J^P$ determination of $Z_c(3900)$ and $Z_c(3900)$ observed in $e^+e^-\toϕχ_{c1, 2}$ at $\sqrt{s}=4.6$~GeV will be presented.
We review recent results on charmonium-like exotic states from the Belle experiment. The two-photon process $γγ\to ϕ\jpsi$ is measured to search for Y(4140). No signal for the $Y(4140) \to ϕ\jpsi$ is observed. But a narrow peak with a significance of 3.2$σ$ deviations including systematic uncertainty is observed at 4350.6 MeV/$c^2$ that we named X(4350). We also search for charmonium-like states, including X(3872), Y(4140), X(3915) and X(4350), in $Υ(1S)$ and $Υ(2S)$ radiative decays. No significant signal of any charmonium-like state is observed. The processes $γγ\to VV$ ($V=ω$ or $ϕ$) are al…
