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Bettoni, D.

Publications and source records attributed to Bettoni, D..

At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Observation of e⁺e⁻ → pp$\bar{p}\bar{n}\pi^-$ + c. c.

Using data taken at 29 center-of-mass energies between 4.16 and 4.70 GeV with the BESIII detector at the Beijing Electron Positron Collider corresponding to a total integrated luminosity of approximately 18.8 fb -1 , the process e⁺e⁻ → pp$\overline{p}\overline{n}\pi^-$ + c. c. is observed for the first time with a statistical significance of 11.5σ. The average Born cross sections in the energy ranges of (4.160, 4.380) GeV, (4.400, 4.600) GeV and (4.610, 4.700) GeV are measured to be (21.5 ± 5.7 ± 1.2) fb, (46.3 ± 10.6 ± 2.5) fb and (59.0 ± 9.4 ± 3.2) fb, respectively, where the first uncertainties are statistical and the second are systematic. The line shapes of the $\overline{p}\overline{n}$ and ppπ⁻ invariant mass spectra are consistent with phase space distributions, indicating that no hexaquark or di-baryon state is observed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Study of η(1405)/η(1475) in $J/\psi \to \gamma {K}_S^0{K}_S^0{\pi}^0$ decay

Using a sample of (10 . 09 ± 0 . 04) × 10 9 J/ψ decays collected with the BESIII detector, partial wave analyses of the decay $ J/\psi \to \gamma {K}_S^0{K}_S^0{\pi}^0$ are performed within the ${K}_S^0{K}_S^0{\pi}^0$ invariant mass region below 1.6 GeV/ c 2 . The covariant tensor amplitude method is used in both mass independent and mass dependent approaches. Both analysis approaches exhibit dominant pseudoscalar and axial vector components, and show good consistency for the other individual components. Furthermore, the mass dependent analysis reveals that the ${K}_S^0{K}_S^0{\pi}^0$ invariant mass spectrum for the pseudoscalar component can be well described with two isoscalar resonant states using relativistic Breit-Wigner model, i.e., the η (1405) with a mass of $1391.7\pm {0.7}_{-0.3}^{+11.3}$ MeV/ c 2 and a width of $60.8\pm {1.2}_{-12.0}^{+5.5}$ MeV, and the η (1475) with a mass of $1507.6\pm {1.6}_{-32.2}^{+15.5}$ MeV/ c 2 and a width of $115.8\pm {2.4}_{-10.9}^{+14.8}$ MeV. The first and second uncertainties are statistical and systematic, respectively. Alternate models for the pseudoscalar component are also tested, but the description of the ${K}_S^0{K}_S^0{\pi}^0$ invariant mass spectrum deteriorates significantly.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Study of e + e - → Ω - Ω ¯ + at center-of-mass energies from 3.49 to 3.67 GeV

Using data samples of e + e - collisions collected with the BESIII detector at eight center-of-mass energy points between 3.49 and 3.67 GeV, corresponding to an integrated luminosity of 670 pb -1 , we present the upper limits of Born cross sections and the effective form factor for the process e + e - → $Ω$ - ⁢$\overline{Ω}$ + . A fit to the cross sections using a perturbative QCD-derived energy-dependent function shows no significant threshold effect. The upper limit on the measured effective form factor is consistent with a theoretical prediction within the uncertainty of 1⁢σ. These results provide new experimental information on the production mechanism of $Ω$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Search for invisible decays of a dark photon using e + e – annihilation data at BESIII

We report a search for a dark photon using 14.9 fb –1 of e + e – annihilation data taken at center-of-mass energies from 4.13 to 4.60 GeV with the BESIII detector operated at the BEPCII storage ring. The dark photon is assumed to be produced in the radiative annihilation process of e + e – and to predominantly decay into light dark matter particles, which escape from the detector undetected. The mass range from 1.5 to 2.9 GeV is scanned for the dark photon candidate, and no significant signal is observed. The mass dependent upper limits at the 90% confidence level on the coupling strength parameter ϵ for a dark photon coupling with an ordinary photon vary between 1.6 x 10 –3 and 5.7 x 10 –3 .

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Measurements of the branching fractions of the inclusive decays D 0 ( D + ) → π + π + π - X

Using e + ⁢e - annihilation data corresponding to an integrated luminosity of 2.93 fb -1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the branching fractions of the inclusive decays D 0 → π + π + π - X and D + → π + π + π - X, where pions from $K^0_S$ decays have been excluded from the → π + π + π - system and X denotes any possible particle combination. The branching fractions of D 0 ⁡(D + ) → π + π + π - X are determined to be B⁡(D 0 → π + π + π - X) = (17.60 ± 0.11 ± 0.22)% and B(D + → π + π + π - X) = (15.25 ± 0.09 ± 0.18)%, where the first uncertainties are statistical and the second systematic.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Study of e+e- → γΦJ/ψ from $\sqrt{s}$ = 4.600 to 4.951 GeV

Using data samples with an integrated luminosity of 6.4 fb -1 collected by the BESIII detector operating at the BEPCII storage ring, the process of e+e- → γΦJ/ψ is studied. The processes of e + e - → Φχc1,c2, χc1,c2 → γJ/ψ are observed with a significance of more than 10σ. The √s-dependent cross section of e + e - → Φχc1,c2 is measured between 4.600 and 4.951 GeV, and evidence of a resonance structure is found for the first time in the Φχc2 process. We also search for the processes of e + e - → γX(4140), γX(4274) and γX(4500) via the γΦJ/ψ final state, but no obvious structures are found. The upper limits on the production cross section times the branching fraction for these processes at the 90% confidence level are reported.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of e + e − → ωπ+π− cross section at $\sqrt{s}$ = 2.000 to 3.080 GeV

A partial wave analysis on the process e⁺e⁻ → ωπ⁺π⁻ is performed using 647 pb -1 of data sample collected by using the BESIII detector operating at the BEPCII storage ring at center-of-mass (c.m.) energies from 2.000 GeV to 3.080 GeV. The Born cross section of the e⁺e⁻ → ωπ⁺π⁻ process is measured, with precision improved by a factor of 3 compared to that of previous studies. A structure near 2.25 GeV is observed in the energy-dependent cross sections of e⁺e⁻ → ωπ⁺π⁻ and ωπ 0 π 0 with a statistical significance of 7.6σ, and its determined mass and width are 2232 ± 19 ± 27 MeV/c 2 and 93 ± 53 ± 20 MeV, respectively, where the first and second uncertainties are statistical and systematic, respectively. By analyzing the cross sections of subprocesses e⁺e⁻ → ωf 0 (500), ωf 0 (980), ωf 0 (1370), ωf 2 (1270), and b1(1235)π, a structure, with mass M = 2200 ± 11 ± 17 MeV/c 2 and width Γ = 74 ± 20 ± 24 MeV, is observed with a combined statistical significance of 7.9σ. The measured resonance parameters will help to reveal the nature of vector states around 2.25 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Search for an axion-like particle in radiative $J/ψ$ decays

We search for an axion-like particle (ALP) a through the process $\psi$(3686) → π + π – J/$\psi$, J/$\psi$ → γa, a → γγ in a data sample of (2.71 ± 0.01) x 10 9 $\psi$(3686) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/$\psi$ → γa and the ALP-photon coupling constant g aγγ are set at 95% confidence level in the mass range of 0.165 ≤ m a ≤ 2.84 GeV/c 2 . The limits on $\mathscr{B}$(J/$\psi$ → γa) range from 8.3 x 10 –8 to 1.8 x 10 –6 over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165 ≤ m a ≤ 1.468 GeV/c 2 .

79 ASTRONOMY AND ASTROPHYSICS↗