Observation of e+e−→γX(3802) at BESIII

Study ofD+→K−π+e+νe

We present an analysis of the decay D+ -> K-pi(+)e(+)nu(e) based on data collected by the BESIII experiment at the psi(3770) resonance. Using a nearly background-free sample of 18262 events, we measure the branching fraction B(D+ -> K-pi+e+nu e) = (3.77 +/- 0.03 +/- 0.08)%. For 0.8 K-pi+e+nu e)([0.8,1.0]) = (3.39 +/- 0.03 +/- 0.08)%. A partial wave analysis shows that the dominant (K) over bar* (892)degrees component is accompanied by an S-wave contribution accounting for (6.05 +/- 0.22 +/- 0.18)% of the total rate and that other components are negligible. The parameters of the (K) over bar* (892)degrees resonance and of the form factors based on the spectroscopic pole dominance predictions…

Measurement of the absolute branching fraction of D + → K̅ 0 e + ν e via K̅ 0 → π 0 π 0

By analyzing 2.93 fb(-1) data collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D+ -> (K) over bar (0)e(+)nu(e) to be B(D (+) -> (K) over bar (0)e(+)nu(e)) = (8.59 +/- 0.14 +/- 0.21)% using (K) over bar (0) -> K-S(0) -> pi(0) pi(0), where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..

Calibration strategy of the JUNO experiment

We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector can achieve a better than 1% energy linearity and a 3% effective energy resolution, required by the neutrino mass ordering determination. [Figure not available: see fulltext.]

Observation of e+e−→ηhc at center-of-mass energies from 4.085 to 4.600 GeV

We observe for the first time the process e(+) e(-) -> eta h(c) with data collected by the BESIII experiment. Significant signals are observed at the center-of-mass energy root s = 4.226 GeV, and the Born cross section is measured to be (9.5(-2.0)(+2.2)) pb. Evidence for eta h(c) is observed at root s = 4.358 GeV with a Born cross section of (10.0(-2.7)(+3.1)) pb, and upper limits on the production cross section at other center-of-mass energies between 4.085 and 4.600 GeV are determined.

Measurement of the e+e− → π+π− cross section between 600 and 900 MeV using initial state radiation

Study ofe+e−→pp¯π0in the vicinity of theψ(3770)

The process e(+)e(-) -> p (p) over bar pi(0) has been studied by analyzing data collected at root s = 3.773 GeV, root s = 3.650 GeV, and during a psi(3770) line shape scan with the BESIII detector at the BEPCII collider. The Born cross section of p (p) over bar pi(0) in the vicinity of the psi(3770) is measured, and the Born cross section of psi(3770) -> p (p) over bar pi(0) is extracted considering interference between resonant and continuum production amplitudes. Two solutions with the same probability and a significance of 1.5 sigma are found. The solutions for the Born cross section of psi(3770) -> p (p) over bar pi(0) are 33.8 +/- 1.8 +/- 2.1 pb and 0.06(-0.04-0.01)(+0.10+0.01) pb ( ->…

Search for the radiative transitionsψ(3770)→γηcandγηc(2S)

By using a 2.92 fb-1 data sample taken at pffisffiffi 3.773 GeV with the BESIII detector operating at the BEPCII collider, we search for the radiative transitions.d3770c and cd2S through the hadronic decays cdcd2S. K0 SK p. No significant excess of signal events above background is observed. We set upper limits at a 90% confidence level for the product branching fractions to be Bdd3770cxBd.c. K0 SK k p < 1.6x10-5 and Bd.d3770cd2SxBd.cd2S. K0 SK p<5.6x10-6. Combining our result with world-average values of Bd.cd.cd2S. K0 SK p, we find the branching fractions Bd.d3770c< 6.8 x 10-4 and Bd.d3770cd2S< 2.0 x 10-3 at a 90% confidence level.

The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS

The European physical journal / C 81(11), 973 (2021). doi:10.1140/epjc/s10052-021-09544-4

Measurement of higher-order multipole amplitudes in ψ(3686)→γχc1,2 with χc1,2→γJ/ψ and search for the transition ηc(2S)→γJ/ψ

Using 106 x 10(6) psi(3686) events collected with the BESIII detector, we measure multipole amplitudes for the decay psi(3686) ->; gamma chi(c1,2) -> gamma gamma J/psi beyond the dominant electric-dipole amplitudes. The normalized magnetic-quadrupole (M2) amplitude for psi(3686) -> gamma chi(c1,2) -> gamma gamma J/psi and the normalized electric-dipole amplitudes for psi(3686) -> gamma chi(c2) -> gamma J/psi and determined. The M2 amplitudes for psi(3686) -> gamma chi(c1) and ; chi(c1,2) -> gamma J/psi are found to differ significantly from zero and are consistent with theoretical predictions. We also obtain the ratios of M2 contributions of psi(3686) and J/psi decays to;2,chi(c1,2,) b(2)(1…

Observation of a Charged Charmoniumlike Structure Zc(4020) and Search for the Zc(3900) in e+e−→π+π−hc

Observation of an Anomalous Line Shape of the η′π+π− Mass Spectrum near the pp¯ Mass Threshold in J/ψ→γη′π+π−

Measurement of the branching fraction forψ(3686)→ωK+K−

With 1.06 x 10(8) psi(3686) events collected with the BESIII detector, the branching fraction of psi(3686) -> omega K+K- is measured to be (1.54 +/- 0.04 +/- 0.11) x 10(-4). This is the most precise result to date, due to the largest psi(3686) sample, improved signal reconstruction efficiency, good simulation of the detector performance, and a more accurate knowledge of the continuum contribution. Using the branching fraction of J/psi -> omega K+K-, the ratio B(psi(3868) -> K+K-)/B(J/psi -> K+K-) is determined to be (18.4 +/- 3.7)%. This constitutes a significantly improved test of the 12% rule, with the uncertainty now dominated by the J/psi branching fraction.

Amplitude analysis of the χc1→ηπ+π− decays

Using 448.0 x 10(6) psi(3686) events collected with the BESIII detector, an amplitude analysis is performed for psi(3686) -> gamma chi(c1), chi(c1) ->eta pi(+)pi(-) decays. The most dominant two- body structure observed is a(0)(980)(+/-) pi(-/+); a(0)(980)(+/-) -> eta pi(+/-.) line shape is modeled using a dispersion relation, and a significant nonzero a(0) (980) coupling to the eta'pi channel is measured. We observe chi(c1) -> a(2)(1700)pi production for the first time, with a significance larger than 17 sigma. The production of mesons with exotic quantum numbers, J(PC) = 1(-+), is investigated, and upper limits for the branching fractions chi(c1) -> pi(1)(1400)(+/-)pi(-/+) , chi(c1) -> pi…

Radioactivity control strategy for the JUNO detector

JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration…

Observation of a Charged Charmoniumlike Structure in e+e−→π+π−J/ψ at s=4.26 GeV

Evidence for the singly Cabibbo suppressed decayΛc+→pηand search forΛc+→pπ0

We study the singly Cabibbo suppressed decays Lambda(+)(c) -> p eta and Lambda(+)(c) -> p pi(0) using Lambda(+)(c)(Lambda) over bar (-)(c) pairs produced by e(+)e(-) collisions at a center-of-mass energy of root s = 4.6 GeV. The data sample was collected by the BESIII detector at the BEPCII collider and corresponds to an integrated luminosity of 567 pb(-1). We find the first evidence for the decay Lambda(+)(c) -> p eta with a statistical significance of 4.2 sigma and measure its branching fraction to be B(Lambda(+)(c) -> p eta) = (1.24 +/- 0.28(stat) +/- 0.10(sys)) x 10(-3). No significant Lambda(+)(c) -> p pi(0) signal is observed. We set an upper limit on its branching fraction B(Lambda(+…

Measurement ofη′→π+π−e+e−andη′→π+π−μ+μ−

Based on a sample of 225.3 million $J/\ensuremath{\psi}$ events accumulated with the BESIII detector at the BEPCII, the decays of ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{l}^{+}{l}^{\ensuremath{-}}$ are studied via $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\eta}}^{\ensuremath{'}}$. A clear ${\ensuremath{\eta}}^{\ensuremath{'}}$ signal is observed in the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$ mass spectrum, and the branching fraction is measured to be $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremat…

Search for the weak decayη′→K±π∓and precise measurement of the branching fractionB(J/ψ→ϕη′)

We present the first search for the rare decay of eta' into K-+/- pi(-/+) in J/psi -> phi eta', using a sample of 1.3 x 10(9) J/psi events collected with the BESIII detector. No significant signal is observed, and the upper limit at the 90% confidence level for the ratio B(eta' -> K-+/- pi(-/+))/B(eta' -> gamma pi(+/-) pi(-/+)) is determined to be 1.3 x 10(-4). In addition, we report the measurement of the branching fraction of J/psi -> phi eta' to be [5.10 +/- 0.03(stat) +/- 0.32(syst)] x 10(-4), which agrees with previous results from BESII.

Search for the rare decaysJ/ψ→Ds−ρ+andJ/ψ→D¯0K¯*0

A search for the rare decays of J/psi -> D-S(-) rho(+) + c.c. and J/psi -> D-S(-)rho(+) + c.c.) <(D)over bar(0)<(K)over bar*(0) + c.c.) < 2.5 x 10(-6) at the 90% confidence level.

JUNO sensitivity to low energy atmospheric neutrino spectra

Atmospheric neutrinos are one of the most relevant natural neutrino sources that can be exploited to infer properties about cosmic rays and neutrino oscillations. The Jiangmen Underground Neutrino Observatory (JUNO) experiment, a 20 kton liquid scintillator detector with excellent energy resolution is currently under construction in China. JUNO will be able to detect several atmospheric neutrinos per day given the large volume. A study on the JUNO detection and reconstruction capabilities of atmospheric $\nu_e$ and $\nu_\mu$ fluxes is presented in this paper. In this study, a sample of atmospheric neutrino Monte Carlo events has been generated, starting from theoretical models, and then pro…

Neutrino Physics with JUNO

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy as a primary physics goal. It is also capable of observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, solar neutrinos, as well as exotic searches such as nucleon decays, dark matter, sterile neutrinos, etc. We present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. By detecting reactor antineutrinos from two power plan…

Measurement of the branching fraction for ψ(3770) → γχc0

Kolcu, Onur Buğra (Arel Author) --- Makale 70 yazarlıdır.

Study ofψdecays to theΞ−Ξ¯+andΣ(1385)∓Σ¯(1385)±final states

We study the decays of the charmonium resonances J/psi and psi(3686) to the final states Xi(-)(Xi) over bar (+), S(1385)(-/+)(Sigma) over bar (1385)(+/-) based on a single baryon tag method using data samples of (223.7 +/- 1.4) x 10(6) J/psi and (106.4 +/- 0.9) x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider. The decay psi(3686) -> Sigma(1385)(-/+)(Sigma) over bar (1385)(+/-) is observed for the first time, and the measurements of the other processes, including the branching fractions and angular distributions, are in good agreement with, and much more precise than, the previously published results. Additionally, the ratios B(psi(3686)->Xi(-)(Xi) over bar …

Observation of pseudoscalar and tensor resonances in J /ψ →γφφ

Based on a sample of (1310.6 +/- 10.5) x 10(6) J/psi events collected with the BESIII detector operating at the BEPCII storage ring, a partial wave analysis of the decay J/psi -> gamma phi phi is performed in order to study the intermediate states. Results of the partial wave analysis show that the structures are predominantly 0(-+) states. The existence of the eta(2225) is confirmed, and its resonance parameters are measured. Two additional pseudoscalar states, the eta(2100) with a mass of 2050(-24-26)(+30+75) MeV/c(2) and a width of 250(-30-164)(+36+181) MeV/c(2) and the X(2500) with a mass of 2470(-19-23)(+15+101) MeV/c(2) and a width of 230(-35-33)(+64+56) MeV/c(2), are observed. In add…

Search forηc(2S)hc→pp¯decays and measurements of theχcJ→pp¯branching fractions

Using a sample of 1.06 x 10(8)psi(3686) events collected with the BESIII detector at BEPCII, the decays eta(c)(2S) -> p (p) over bar and h(c) -> p (p) over bar are searched for, where eta(c)(2S) and h(c) are reconstructed in the decay chains psi(3686) -> gamma eta(c)(2S), eta(c)(2S) -> p (p) over bar and psi(3686) -> pi(0)h(c), h(c) -> p (p) over bar, respectively. No significant signals are observed. The upper limits of the product branching fractions are determined to be B(psi(3686) -> gamma eta(c)(2S)) x B(eta(c)(2S) -> p (p) over bar) pi(0)h(c)) x B(h(c) -> p ) p (J = 0, 1, 2) are also measured to be (24.5 +/- 0.8 +/- 1.3, 8.6 +/- 0.5 +/- 0.5, 8.4 +/- 0.5 +/- 0.5) x 10(-5), which are th…

Precision measurements of B(D+→μ+νμ), the pseudoscalar decay constant fD+, and the quark mixing matrix element |Vcd|

We report a measurement of the branching fraction B(D+ -> mu(+)nu(mu)) = [3.71 +/- 0.19(stat) +/- 0.06(sys)] x 10(-4) based on 2.92 fb(-1) of data accumulated at root s = 3.773 GeV with the BESIII detector at the BEPCII collider. This measurement, in conjunction with the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cd vertical bar determined from a global Standard Model fit, implies a value for the weak decay constant f(D+) = (203.2 +/- 5.3 +/- 1.8) MeV. Additionally, using this branching fraction measurement together with a lattice QCD prediction for f(D+), we find vertical bar V-cd vertical bar 0.2210 +/- 0.0058 +/- 0.0047. In either case, these are the most precise results for…