Xiongyi Liu

• PhD
• Professor (Associate) at Cleveland State University

CompactLight is a Design Study funded by the European Union under the Horizon 2020 research and innovation funding programme, with Grant Agreement No. 777431. CompactLight was conducted by an International Collaboration of 23 international laboratories and academic institutions, three private companies, and five third parties. The project, which st...

This article presents a systematic review on autism care, diagnosis, and intervention based on mobile apps running on smartphones and tablets. Here, the term “intervention” means a carefully planned set of activities with the objective of improving autism symptoms. We guide our review on related studies using five research questions. First, who ben...

The CompactLight design for a next-generation x-ray free-electron laser utilizes a C-band injector. This requires that the harmonic system used to linearize the beam’s phase space must operate at X-band rf or higher. We investigate the optimum frequency for the harmonic system in the range of frequencies from 12 to 48 GHz. We describe the reasoning...

The purpose of the present study is to develop a scale for measuring pre-service teacher perceptions of gender stereotypes about computer game-based learning, and conduct a preliminary study to explore the reliability and validity of the scale. Data was collected via survey from 119 pre-service teachers enrolled in a mathematics methods class at a...

The report presents, as the main result of the CompactLight project, the conceptual design of the CompactLight hard X-ray FEL. It is divided in the following chapters: 1. Executive Summary 2. Introduction 3. Science Goals and Photon Output Requirements 4. Systems Design and Performance 5. Accelerator 6. Light Production 7. Civil Engineering...

The purpose of this exploratory study was to examine whether specific attitudes and beliefs among pre-service teachers about the use of computer games in mathematics teaching and learning predict their intention to integrate computer games in future mathematics teaching. Data were collected via a questionnaire from 119 teacher education students in...

As part of the deign studies, the CompactLight project plans to use an injector in the C-band. Which constitutes a particular complication for the harmonic system in charge of linearising the beam's phase space, since it means its operation frequency could be higher than the standard X-band RF technologies. In the present work, we investigated a 36...

For the first time, planar high-purity germanium detectors with thin amorphous germanium contacts were successfully operated directly in liquid nitrogen and liquid argon in a cryostat at the Max-Planck-Institut für Physics in Munich. The detectors were fabricated at the Lawrence Berkeley National Laboratory and the University of South Dakota, using...

For the first time, planar high-purity germanium detectors with thin amorphous germanium contacts were successfully operated directly in liquid nitrogen and liquid argon in a cryostat at the Max-Planck-Institut fuer Physics in Munich. The detectors were fabricated at the Lawrence Berkeley National Laboratory and the University of South Dakota, usin...

The rapid development of computer and sensing technologies enables e-coaching systems for individuals with various physical health and mental health challenges. In this article, we review recent research efforts on using virtual avatar-based computer technologies to improve social and communication skills of children with autism spectrum disorder (...

CompactLight (XLS) is an International Collaboration of 24 partners and 5 third parties, funded by the European Union through the Horizon 2020 Research and Innovation Programme. The main goal of the project, which started in January 2018 with a duration of 36 months, is the design of an hard X-ray FEL facility beyond today's state of the art, using...

The H2020 CompactLight Project aims at designing the next generation of compact X-rays Free-Electron Lasers, relying on very high gradient accelerating structures (X-band, 12 GHz), the most advanced concepts for high brightness electron photo injectors, and innovative compact short-period undulators. Compared to existing facilities, the proposed fa...

The CompactLight project is currently developing the design of a next generation hard X-ray FEL facility, based on high-gradient X-band (12 GHz) structures, bright electron photo-injectors, and compact short period undulators. However, to improve the brightness limitations due to the non-linear energy spread of the electron bunches, a Ka-band (36 G...

The purpose of the present study is to investigate pre-service teachers' previous mathematics learning experience from elementary school to college and how it relates to their attitudes and beliefs about mathematics learning and teaching. Data were collected over two semesters from a total of 67 pre-service teachers in a mathematics methods course...

Amplitude models are constructed to describe the resonance structure of \({D^{0}\rightarrow K^{-}\pi ^{+}\pi ^{+}\pi ^{-}}\) and \({D^{0} \rightarrow K^{+}\pi ^{-}\pi ^{-}\pi ^{+}}\) decays using pp collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of 3.0 \(fb^{-1}...

The charm semileptonic decays D+→ηe+νe and D+→η′e+νe are studied with a sample of e+e− collision data corresponding to an integrated luminosity of 2.93 fb−1 collected at s=3.773 GeV with the BESIII detector. We measure the branching fractions for D+→ηe+νe to be (10.74±0.81±0.51)×10−4, and for D+→η′e+νe to be (1.91±0.51±0.13)×10−4, where the uncerta...

A search for the rare decay Σ+→pμ+μ− is performed using pp collision data recorded by the LHCb experiment at center-of-mass energies s=7 and 8 TeV, corresponding to an integrated luminosity of 3 fb−1. An excess of events is observed with respect to the background expectation, with a signal significance of 4.1 standard deviations. No significant str...

Using a data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected at a center-of-mass energy of $\sqrt{s}=4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic $\Lambda_c^+$ decay with a double-tag method. We obtain $\mathcal{B}(\Lambda_c^+ \rightarrow X e^+ \nu_e) = (3.95...

Using a data sample of $(1310.6 \pm 7.0)\times 10^6$ $J/\psi$ events collected with the BESIII detector operating at the BEPCII collider, we perform the first experimental search for invisible decays of a light vector meson ($V=\omega,\phi$) via $J/\psi \to V \eta$ decays. The decay of $\eta \to \pi^+\pi^-\pi^0$ is utilized to tag the $V$ meson dec...

A search for the flavor-changing neutral-current decay Λc+→pμ+μ− is reported using a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb Collaboration. No significant signal is observed outside of the dimuon mass regions around the ϕ and ω resonances, and an upper limit is placed on the branching fraction of B(Λc+→p...

Based on a data sample of (448.1±2.9)×106ψ(3686) decays collected with the BESIII experiment, a search for the flavor changing neutral current transition ψ(3686)→Λc+p¯e+e−+c.c. is performed for the first time. No signal candidates are observed and the upper limit on the branching fraction of ψ(3686)→Λc+p¯e+e− is determined to be 1.7×10−6 at the 90%...

Using a data sample of 448.1×10⁶ ψ(3686) events collected with the BESIII detector at the BEPCII collider, we report the first observation of the electromagnetic Dalitz decay ψ(3686)→η′e⁺e⁻, with significances of 7.0σ and 6.3σ when reconstructing the η′ meson via its decay modes η′→γπ⁺π⁻ and η′→π⁺π⁻η (η→γγ), respectively. The weighted average branc...

We search for rare decays of D mesons to hadrons accompanied by an electron-positron pair (h(h(′))e+e−), using an e+e− collision sample corresponding to an integrated luminosity of 2.93 fb−1 collected with the BESIII detector at s=3.773 GeV. No significant signals are observed, and the corresponding upper limits on the branching fractions at the 90...

Using a sample of 4.48×108 ψ(3686) events collected with the BESIII detector at the BEPCII collider, we study the two-photon decays of the pseudoscalar mesons π0, η, η′, η(1405), η(1475), η(1760), and X(1835) in J/ψ radiative decays using ψ(3686)→π+π−J/ψ events. The π0, η, and η′ mesons are clearly observed in the two-photon mass spectra, and the b...

The ratio of branching fractions R(D*−)≡B(B0→D*−τ+ντ)/B(B0→D*−μ+νμ) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb−1. The τ lepton is reconstructed with three charged pions in the final state. A novel method is...

Using $1.31 \times 10^9$ $J/\psi$ events collected by the BESIII detector at the BEPCII $e^+e^-$ collider, we report the first observation of the $h_1(1380)$ in $J/\psi \to \eta^{\prime} h_1(1380)$ with a significance of more than ten standard deviations. The mass and width of the possible axial-vector strangeonium candidate $h_1(1380)$ are measure...

We investigate the process e+e−→KK¯J/ψ at center-of-mass energies from 4.189 to 4.600 GeV using 4.7 fb−1 of data collected by the BESIII detector at the BEPCII collider. The Born cross sections for the reactions e+e−→K+K−J/ψ and KS0KS0J/ψ are measured as a function of center-of-mass energy. The energy dependence of the cross section for e+e−→K+K−J/...

Using a data sample of e+e− collision data with an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy s=3.773 GeV with the BESIII detector operating at the BEPCII storage rings, we measure the absolute branching fractions of the two-body hadronic decays D+→π+π0, K+π0, π+η, K+η, π+η′, K+η′, KS0π+, KS0K+, and D0→π+π−, K+K−, K∓π±, K...

Using a data sample of e+e− collision data corresponding to an integrated luminosity of 2.93 fb−1 collected with the BESIII detector at a center-of-mass energy of s=3.773GeV, we search for the singly Cabibbo-suppressed decays D0→π0π0π0, π0π0η, π0ηη and ηηη using the double tag method. The absolute branching fractions are measured to be B(D0→π0π0π0)...

The process e+e−→Ds*+Ds0*(2317)−+c.c. is observed for the first time with the data sample of 567 pb−1 collected with the BESIII detector operating at the BEPCII collider at a center-of-mass energy s=4.6 GeV. The statistical significance of the Ds0*(2317)± signal is 5.8σ and the mass is measured to be (2318.3±1.2±1.2) MeV/c2. The absolute branching...

Using a data sample of $448.1 \times 10^6$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, we report the first observation of the electromagnetic Dalitz decay $\psi(3686) \to \eta' e^+ e^-$, with significances of 7.0$\sigma$ and 6.3$\sigma$ when reconstructing the $\eta'$ meson via its decay modes $\eta'\to\gamma \pi^...

Using a data sample of 448.1×106 ψ(3686) events collected with the BESIII detector operating at the BEPCII, we perform search for the hadronic transition hc→π+π−J/ψ via ψ(3686)→π0hc. No signals of the transition are observed, and the upper limit on the product branching fraction B(ψ(3686)→π0hc)B(hc→π+π−J/ψ) at the 90% confidence level (C.L.) is det...

We report new measurements of the cross sections for the production of D Dbar final states at the psi(3770) resonance. Our data sample consists of an integrated luminosity of 2.93/fb of e+e- annihilation data produced by the BEPCII collider and collected and analyzed with the BESIII detector. We exclusively reconstruct three D0 and six D+ hadronic...

By analyzing a data sample of 2.93 fb−1 collected at s=3.773 GeV with the BESIII detector operated at the BEPCII storage rings, we measure the branching fractions B(D0→ωη)=(2.15±0.17stat±0.15sys)×10−3, B(D0→ηπ0)=(0.58±0.05stat±0.05sys)×10−3, B(D0→η′π0)=(0.93±0.11stat±0.09sys)×10−3, B(D0→ηη)=(2.20±0.07stat±0.06sys)×10−3 and B(D0→η′η)=(0.94±0.25stat±...

Using a data sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 2.93 $fb^{-1}$ collected with the BESIII detector at a center-of-mass energy of $\sqrt{s}= 3.773~GeV$,we search for the singly Cabibbo-suppressed decays $D^{0}\to\pi^{0}\pi^{0}\pi^{0}$, $\pi^{0}\pi^{0}\eta$, $\pi^{0}\eta\eta$ and $\eta\eta\eta$ using the dou...

Based on an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567$\,\rm{pb}^{-1}$ taken at the center-of-mass energy of $\sqrt{s} = 4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay $\Lambda_{c}^{+} \to \Lambda + X$ to be $\mathcal{B}(\Lambda_{c}^{+} \to \Lambda + X)=(38.2...

The charm semileptonic decays $D^+\to\eta e^+\nu_{e}$ and $D^+\to\eta'e^+\nu_{e}$ are studied with a sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 2.93 fb$^{-1}$ collected at $\sqrt{s}$ = 3.773 GeV with the BESIII detector. We measure the branching fractions for $D^+\to\eta e^+\nu_{e}$ to be $(10.74\pm0.81\pm0.51)\t...

Using $1.31\times10^9$ $J/\psi$ events collected by the BESIII detector at the Beijing Electron Positron Collider, we search for the process $J/\psi\to\Lambda_c^+e^-+c.c.$ for the first time. In this process, both baryon and lepton number conservation is violated. No signal is found and the upper limit on the branching fraction $\mathcal{B}(J/\psi\...

We report the first measurements of absolute branching fractions for the $W$-exchange-only processes $\Lambda^+_c\to\Xi^0K^+$ and $\Lambda^+_c\to\Xi(1530)^0K^+$ with the double-tag technique, by analyzing an $e^{+}e^{-}$ collision data sample, that corresponds to an integrated luminosity of 567~pb$^{-1}$ collected at a center-of-mass energy of 4.6~...

To investigate the nature of the $\psi(3770)$ resonance and to measure the cross section for $e^+e^- \to D\bar{D}$, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89~GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scatte...

Using e+e− collision data collected with the BESIII detector at the BEPCII collider corresponding to an integrated luminosity of 5.2 fb−1 at center-of-mass energies (s) from 4.009 to 4.600 GeV, the process e+e−→π0π0ψ(3686) is studied for the first time. The corresponding Born cross sections are measured and found to be half of those of the reaction...

The decay J/ψ→γγϕ is studied using a sample of 1.31×109 J/ψ events collected with the BESIII detector. Two structures around 1475 MeV/c2 and 1835 MeV/c2 are observed in the γϕ invariant mass spectrum for the first time. With a fit on the γϕ invariant mass, which takes into account the interference between the two structures, and a simple analysis o...

We observe the decay $\psi(3686) \to n \bar{n}$ for the first time and measure $\psi(3686) \to p \bar{p}$ with improved accuracy by using $1.07\times 10^8$ $\psi(3686)$ events collected with the BESIII detector. The measured branching fractions are $\mathcal{B}(\psi(3686) \to n \bar{n}) = (3.06 \pm 0.06 \pm 0.14)\times 10^{-4}$ and $\mathcal{B}(\ps...

Using an $e^+e^-$ collision data sample of 2.93 fb$^{-1}$ collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of $D^0 \to a_0(980)^- e^+ \nu_e$ and evidence for $D^+ \to a_0(980)^0 e^+ \nu_e~$ with significances of $6.4\sigma$ and $2.9\sigma$, respectively. The absolute branching fractions a...

The process e+e−→ΛΛ¯ is studied using data samples at 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 s=2.2324 GeV, which is 1.0 MeV above the ΛΛ¯ mass threshold, to be 305±45−36+66 pb, where the first uncertainty is statistical and the second systematic...

We search for rare decays of $D$ mesons to hadrons accompany with an electron-positron pair (h(h')$e^+e^-$), using an $e^+e^-$ collision sample corresponding to an integrated luminosity of 2.93 fb$^{-1}$ collected with the BESIII detector at $\sqrt{s}$ = 3.773 GeV. No significant signals are observed, and the corresponding upper limits on the branc...

Using a sample of $4.48\times10^{8}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, we study the two-photon decays of the pseudoscalar mesons $\pi^0$, $\eta$, $\eta^\prime$, $\eta(1405)$, $\eta(1475)$, $\eta(1760)$, and $X(1835)$ in $J/\psi$ radiative decays using $\psi(3686)\to\pi^{+}\pi^{-}J/\psi$ events. The $\pi^...

We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of D0→K+π− to D0→K−π+ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of 5.0 fb−1 recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters a...

Investigations of the existence of pentaquark states containing a single b (anti)quark decaying weakly into four specific final states J/ψK+π−p, J/ψK−π−p, J/ψK−π+p, and J/ψϕ(1020)p are reported. The data sample corresponds to an integrated luminosity of 3.0 fb−1 in 7 and 8 TeV pp collisions acquired with the LHCb detector. Signals are not observed...

Using a data sample corresponding to an integrated luminosity of $2.93\,\rm fb^{-1}$ taken at a center-of-mass energy of 3.773\,GeV with the BESIII detector operated at the BEPCII collider, we perform an analysis of the semi-leptonic decays $D^{0(+)}\to \pi^{-(0)}\mu^+\nu_\mu$. The branching fractions of ${\mathcal B}(D^0\to \pi^-\mu^+\nu_\mu)$ and...

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of s=4.600 GeV, we search for the production of e+e−→ϕχc0,1,2. A search is also performed for the charmonium-like state X(4140) in the radiative transition e+e−→γX(4140) with X(4140) subsequently decaying into ϕJ/ψ. The processes e...

Using a data sample of $e^+e^-$ collision data with an integrated luminosity of 2.93 fb$^{-1}$ taken at the center-of-mass energy $\sqrt s= 3.773$~GeV with the BESIII detector operating at the BEPCII storage rings, we measure the absolute branching fractions of the two-body hadronic decays $D^+\to \pi^+\pi^0$, $K^+ \pi^0$, $\pi^+ \eta$, $K^+\eta$,...

We investigate the process $e^{+}e^{-} \rightarrow K\bar{K}J/\psi$ at center-of-mass energies from 4.189 to 4.600 GeV using 4.7 fb$^{-1}$ of data collected by the BESIII detector at the BEPCII collider. The Born cross sections for the reactions $e^{+}e^{-} \rightarrow K^{+}K^{-}J/\psi$ and $K_{S}^{0} K_{S}^{0} J/\psi$ are measured as a function of...

We report the first observation of $a^{0}_{0}(980)$-$f_{0}(980)$ mixing in the decays of $J/\psi\to\phi f_{0}(980) \to a^{0}_{0}(980) \to\phi\eta\pi^{0}$ and $\chi_{c0}\to a^{0}_{0}(980) \pi^{0}\to f_{0}(980)\pi^{0} \to \pi^{+}\pi^{-}\pi^{0}$, using data samples of $1.31\times10^{9}$ $J/\psi$ events and $4.48\times10^{8}$ $\psi(3686)$ events accumu...

Using a data sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 108 pb$^{-1}$ collected with the BESIII detector at a center-of-mass energy of 2.125 GeV, we study the process $e^+e^-\rightarrow \phi\pi\pi$, and search for a strangeonium-like structure $Z_s$ decaying into $\phi \pi$. No signal is observed in the $\phi\pi$...

By analyzing 482 pb−1 of e+e− collision data collected at the center-of-mass energy s=4.009 GeV with the BESIII detector, we measure the branching fractions for the semi-leptonic decays Ds+→ϕe+νe, ϕμ+νμ, ημ+νμ and η′μ+νμ to be B(Ds+→ϕe+νe)=(2.26±0.45±0.09)%, B(Ds+→ϕμ+νμ)=(1.94±0.53±0.09)%, B(Ds+→ημ+νμ)=(2.42±0.46±0.11)% and B(Ds+→η′μ+νμ)=(1.06±0.54...

A search is performed in the invariant mass spectrum of the B c + π + π − system for the excited B c + states B c (2 1 S 0 ) + and B c (2 3 S 1 ) + using a data sample of pp collisions collected by the LHCb experiment at the centre-of-mass energy of s=8 TeV, corresponding to an integrated luminosity of 2 fb −1 . No evidence is seen for either state...

By analyzing a data sample of 2.93 fb$^{-1}$ collected at $\sqrt s=$ 3.773 GeV with the BESIII detector operated at the BEPCII storage rings, we measure the branching fractions ${\mathcal B}(D^0\to\omega\eta)=(2.15\pm0.17_{\rm stat.}\pm0.15_{\rm sys.})\times 10^{-3}$, ${\mathcal B}(D^0\to\eta\pi^0)=(0.58\pm0.05_{\rm stat.}\pm0.05_{\rm sys.})\times...

Based on a sample of 1.31×109 J/ψ events collected with the BESIII detector, the matrix elements for the decays η′→ηπ+π− and η′→ηπ0π0 are determined using 351,016 η′→(η→γγ)π+π− and 56,249 η′→(η→γγ)π0π0 events with background levels less than 1%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumpti...

Using a data sample of $448.1\times10^6$ $\psi(3686)$ events collected with the BESIII detector operating at the BEPCII, we perform search for the hadronic transition $h_c\rightarrow\pi^+\pi^-J/\psi$ via $\psi(3686)\rightarrow\pi^0h_c$. No signals of the transition are observed, and the upper limit on the product branching fraction $\mathcal{B}(\ps...

The decay $J/\psi \rightarrow \gamma \gamma \phi$ is studied using a sample of $1.31 \times10^{9}$ $J/\psi$ events collected with the BESIII detector. Two structures around 1475 MeV/c$^2$ and 1835 MeV/c$^2$ are observed in the $\gamma \phi$ invariant mass spectrum for the first time. With a fit on the $\gamma \phi$ invariant mass, which takes into...

The LZ dark matter detector, like many other rare-event searches, will suffer from backgrounds due to the radioactive decay of radon daughters. In order to achieve its science goals, the concentration of radon within the xenon should not exceed 2 µBq/kg, or 20 mBq total within its 10 tonnes. The LZ collaboration is in the midst of a program to scre...

Using the data samples of 1.31×109 J/ψ events and 4.48×108 ψ(3686) events collected with the BESIII detector, partial wave analyses on the decays J/ψ and ψ(3686)→π+π−η′ are performed with a relativistic covariant tensor amplitude approach. The dominant contribution is found to be J/ψ and ψ(3686) decays to ρη′. In the J/ψ decay, the branching fracti...

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of $\sqrt{s}=4.600$ GeV, we search for the production of $e^{+}e^{-} \to \phi\chi_{c0,1,2}$ and the charmonium-like state $Y(4140)$ in the radiative transition $e^{+}e^{-} \to \gamma Y(4140)$ with $Y(4140)$ subsequently decaying in...

Using a sample of 448.1×106 ψ(3686) events collected with the BESIII detector, a search for the isospin violating decay ηc→π+π−π0 via ψ(3686)→γηc is presented. No signal is observed, and the upper limit on B(ψ(3686)→γηc)×B(ηc→π+π−π0) is determined to be 1.6×10−6 at the 90% confidence level. In addition, a search for η(1405)→f0(980)π0 in ψ(3686) rad...

Using a sample of 448.1×106 ψ(3686) events collected with the BESIII detector in 2009 and 2012, we study the decays χc0,2→η′η′ and ηη′. The decays χc2→η′η′, χc0→ηη′ and χc2→ηη′ are observed for the first time with statistical significances of 9.6σ, 13.4σ and 7.5σ, respectively. The branching fractions are determined to be B(χc0→η′η′)=(2.19±0.03±0.1...

A measurement of the shape of the differential decay rate and the associated Isgur-Wise function for the decay Λb0→Λc+μ−ν¯μ is reported, using data corresponding to 3 fb−1 collected with the LHCb detector in proton-proton collisions. The Λc+μ−ν¯μ(+anything) final states are reconstructed through the detection of a muon and a Λc+ baryon decaying int...

A search for decays of $B_c^+$ mesons to two charm mesons is performed for the first time using data corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The decays considered are $B_c^+\to D^{(*)+}_{(s)} \overline{D}^{(*)0}$ and $B_c^+\to D^{(*)+}...

The decays of χc2→K+K−π0, KSK±π∓, and π+π−π0 are studied with the ψ(3686) data samples collected with the Beijing Spectrometer (BESIII). For the first time, the branching fractions of χc2→K*K¯, χc2→a2±(1320)π∓/a20(1320)π0, and χc2→ρ(770)±π∓ are measured. Here, K*K¯ denotes both K*±K∓ and its isospin-conjugated process K*0K¯0+c.c., and K* denotes th...

Using the data samples of (1310.6±7.2)×106 J/ψ events and (448.1±2.9)×106 ψ(3686) events collected with the BESIII detector, we search for the rare decays J/ψ→D0e+e−+c.c. and ψ(3686)→D0e+e−+c.c. No significant signals are observed and the corresponding upper limits on the branching fractions at the 90% confidence level are determined to be B(J/ψ→D0...

Using a low background data sample of $9.7\times10^{5}$ $J\psi\rightarrow\gamma\eta^\prime$, $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ events recorded with the BESIII detector at BEPCII, the decay dynamics of $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ are studied with both model-dependent and -independent approaches. The contributions of $\omega$ and...

Using a sample of 1.31×109 J/ψ events collected with the BESIII detector at the BEPCII collider, we study the decays of J/ψ→KSKL and KSKS. The branching fraction of J/ψ→KSKL is determined to be B(J/ψ→KSKL)=(1.93±0.01(stat)±0.05(syst))×10−4, which significantly improves on previous measurements. No clear signal is observed for the J/ψ→KSKS process,...

The decays χc1→J/ψμ+μ− and χc2→J/ψμ+μ− are observed and used to study the resonance parameters of the χc1 and χc2 mesons. The masses of these states are measured to be m(χc1)=3510.71±0.04(stat)±0.09(syst) MeV and m(χc2)=3556.10±0.06(stat)±0.11(syst) MeV, where the knowledge of the momentum scale for charged particles dominates the systematic uncert...

Based on 448.1×106 ψ(3686) events collected with the BESIII detector, the decays ψ(3686)→γχcJ,χcJ→γγ(J=0,1,2) are studied. The decay branching fractions of χc0,2→γγ are measured to be B(χc0→γγ)=(1.93±0.08±0.05±0.05)×10-4 and B(χc2→γγ)=(3.10±0.09±0.07±0.11)×10-4, which correspond to two-photon decay widths of Γγγ(χc0)=2.03±0.08±0.06±0.13 keV and Γγγ...

The process $e^+ e^- \to D_{s}^{*+} D_{s0}^{*-}(2317)+c.c.$ is observed for the first time with the data sample of 567~pb$^{-1}$ collected with the BESIII detector operating at the BEPCII collider at a center-of-mass energy $\sqrt{s} = 4.6$~GeV. The statistical significance of the $D_{s0}^{*-}(2317)$ signal is $5.8\sigma$ and the mass is measured t...

Using $e^{+}e^{-}$ collision data collected with the BESIII detector at the BEPCII collider corresponding to an integrated luminosity of 5.2 $fb^{-1}$ at center-of-mass energies ($\sqrt{s}$) from 4.009 to 4.600 GeV, the process $e^{+}e^{-} \to \pi^{0} \pi^{0}\psi(3686)$ is studied for the first time. The corresponding Born cross sections are measur...

Using a sample of $1.31 \times 10^{9}$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider, we study the decays of $J/\psi \rightarrow K_S K_L$ and $K_S K_S$. The branching fraction of$J/\psi\rightarrow K_S K_L$ is determined to be ${\cal B}(J/\psi \rightarrow K_S K_L)=(1.93\pm0.01~(\rm{stat.})\pm0.05~(\rm{syst.}))\times10^{-4...

The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 − 50 meV, will require a tonne-scale experime...

The rapid development of computer and robotic technologies in the last decade is giving hope to perform earlier and more accurate diagnoses of the Autism Spectrum Disorder (ASD), and more effective, consistent, and cost-conscious treatment. Besides the reduced cost, the main benefit of using technology to facilitate treatment is that stimuli produc...

The production of $B^{\pm}$ mesons is studied in $pp$ collisions at centre-of-mass energies of 7 and 13 TeV, using $B^{\pm}\rightarrow J/\psi K^{\pm}$ decays and data samples corresponding to 1.0 fb$^{-1}$ and 0.3 fb$^{-1}$, respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range $0<p_{...

A search for the lepton-flavour violating decays $B^0_s \rightarrow e^\pm \mu^\mp$ and $B^0 \rightarrow e^\pm \mu^\mp$ is performed based on a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb$^{-1}$, collected with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The observed yields are consiste...

Searches are performed for both prompt-like and long-lived dark photons, $A^{\prime}$, produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using $A^{\prime}\to\mu^+\mu^-$ decays and a data sample corresponding to an integrated luminosity of 1.6 fb$^{-1}$ collected with the LHCb detector. The prompt-like $A^{\prime}$ search co...