The highest energy gamma-rays from gamma-ray bursts (GRBs) have important implications for their radiation mechanism. Here we report for the first time the detection of gamma-rays up to 13 TeV from the brightest GRB 221009A by the Large High Altitude Air-shower Observatory (LHAASO). The LHAASO-KM2A detector registered more than 140 gamma-rays with energies above 3 TeV during 230$-$900s after the trigger. The intrinsic energy spectrum of gamma-rays can be described by a power-law after correcting for extragalactic background light (EBL) absorption. Such a hard spectrum challenges the synchrotron self-Compton (SSC) scenario of relativistic electrons for the afterglow emission above several TeV. Observations of gamma-rays up to 13 TeV from a source with a measured redshift of z=0.151 hints more transparency in intergalactic space than previously expected. Alternatively, one may invoke new physics such as Lorentz Invariance Violation (LIV) or an axion origin of very high energy (VHE) signals.

Air shower

Extragalactic background light

10.48550/arxiv.2310.08845

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Amplitude analysis of the χc1→ηπ+π− decays

Physical review. D/Physical review. D. (2017)

F. De Mori М. Н. Ачасов S. Ahmed X. Ai O. Albayrak

Using $448.0 \times 10^6$~$\psi(3686)$ events collected with the BESIII detector, an amplitude analysis is performed for $\psi(3686)\to\gamma\chi_{c1}$, $\chi_{c1}\to\eta\pi^+\pi^-$ decays. The most dominant two-body structure observed is $a_0(980)^{\pm}\pi^{\mp}$; $a_0(980)^{\pm}\to\eta\pi^{\pm}$. The $a_0(980)$ line shape is modeled using a dispersion relation, and a significant non-zero $a_0(980)$ coupling to the $\eta^{\prime}\pi$ channel is measured. We observe $\chi_{c1}\to a_2(1700)\pi$ 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 $\chi_{c1}\to \pi_1(1400)^{\pm}\pi^{\mp}$, $\chi_{c1}\to \pi_1(1600)^{\pm}\pi^{\mp}$, and $\chi_{c1}\to\pi_1(2015)^{\pm}\pi^{\mp}$, with subsequent $\pi_1(X)^{\pm} \to \eta\pi^{\pm}$ decay, are determined.

Electron–positron annihilation

Partial wave analysis

10.1103/physrevd.95.032002

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Citations (54)

Issue Information

Influenza and Other Respiratory Viruses (2020)

Benjamin J. Cowling Hong Kong Senior Rebecca Jane Cox Alan Hampson Jackie Katz

Aim and ScopeInfluenza and other respiratory viruses is the Official Journal of the International Society of Influenza and other respiratory virus diseases -an independent scientific professional society -dedicated to promoting the prevention, detection, treatment, and control of Influenza and other respiratory virus diseases.Influenza and other respiratory viruses is the first journal to specialise exclusively on Influenza and other respiratory viruses and strives to play a key role in the disemmination of information in this broad and challenging field.This journal is aimed at laboratory and clinical scientists, public health professionals, and others around the world involved in a broad range of activities in this field.In turn topics covered will include; • surveillance • epidemiology • prevention and treatment by antivirals • prevention by vaccines • clinical studies • public health and pandemic preparedness • basic scientific research • transmission between animals and humans

10.1111/irv.12652

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Precision measurement of the branching fraction of \boldmath $J/\psi\rightarrow K^+K^-$ via $\psi(2S)\rightarrow \pi^+\pi^-J/\psi$

arXiv (Cornell University) (2024)

BESIII Collaboration M. Ablikim М. Н. Ачасов P. Adlarson X. Ai

Using a sample of $448.1 \times 10^6$ $\psi(2S)$ events collected with the BESIII detector, we perform a study of the decay $J/\psi\rightarrow K^+K^-$ via $\psi(2S)\rightarrow \pi^+\pi^-J/\psi$. The branching fraction of $J/\psi\rightarrow K^+K^-$ is determined to be $\mathcal{B}_{K^+K^-}=(3.072\pm 0.023({\rm stat.})\pm 0.050({\rm syst.}))\times 10^{-4}$, which is consistent with previous measurements but with significantly improved precision.

Branching (polymer chemistry)

Branching fraction

10.48550/arxiv.2405.12809

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The σ pole in J/ ψ→ ωπ + π −

arXiv (Cornell University) (2004)

F. De Mori J.Z. Bai Y. Ban J. G. Bian D.V. Bugg

Systematic error

Position (finance)

Source

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Citations (118)

Determination of spin and parity of $D^{*}_{(s)}$ mesons

arXiv (Cornell University) (2023)

BESIII Collaboration F. De Mori М. Н. Ачасов P. Adlarson R. Aliberti

The spin and parity of the charmed mesons $D_{s}^{*+}$, $D^{*0}$ and $D^{*+}$ are determined for the first time to be $J^P=1^{-}$ with significances greater than 10$\sigma$ over other hypotheses of $2^{+}$ and $3^{-}$, using an $e^+e^-$ collision data sample with an integrated luminosity of 3.19 fb$^{-1}$ collected by the BESIII detector at a center-of-mass energy of 4.178 GeV. Different spin-parity hypotheses for $D_{s}^{*+}$, $D^{*0}$, and $D^{*+}$ mesons are tested via a helicity amplitude analysis of the processes $e^+e^-\to D^{*+}_{s}D^{-}_{s}$, $D^{*0}D^{0}$ and $D^{*+}D^{-}$, with $D^{*+}_{s}\to D^{+}_{s} \gamma$, $D^{*0}\to D^{0}\pi^{0}$, and $D^{*+}\to D^{+}\pi^{0}$. The results confirm the quark model predictions.

Parity (physics)

Helicity

Sigma

10.48550/arxiv.2305.14631

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Hadronic cross section measurements with the DAMPE space mission using 20GeV-10TeV cosmic-ray protons and $^4$He

arXiv (Cornell University) (2024)

F. Alemanno Q. An P. Azzarello F. C. T. Barbato P. Bernardini

Precise direct cosmic-ray (CR) measurements provide an important probe to study the energetic particle sources in our Galaxy, and the interstellar environment through which these particles propagate. Uncertainties on hadronic models, ion-nucleon cross sections in particular, are currently the limiting factor towards obtaining more accurate CR ion flux measurements with calorimetric space-based experiments. We present an energy-dependent measurement of the inelastic cross section of protons and helium-4 nuclei (alpha particles) on a Bi$_4$Ge$_3$O$_{12}$ target, using 88 months of data collected by the DAMPE space mission. The kinetic energy range per nucleon of the measurement points ranges from 18 GeV to 9 TeV for protons, and from 5 GeV/n to 3 TeV/n for helium-4 nuclei. Our results lead to a significant improvement of the CR flux normalisation. In the case of helium-4, these results correspond to the first cross section measurements on a heavy target material at energies above 10 GeV/n.

Section (typography)

10.48550/arxiv.2408.17224

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Monitoring the daily variation of Sun-Earth magnetic fields using galactic cosmic rays

The Innovation (2024)

Z. Cao F Aharonian M Axikegu Y. X. Bai Yiwang Bao

Variation (astronomy)

10.1016/j.xinn.2024.100695

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Study of $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ at $\sqrt{s}$ from 2.00 to 3.08 GeV at BESIII

arXiv (Cornell University) (2024)

BESIII Collaboration F. De Mori М. Н. Ачасов P. Adlarson X. Ai

With the data samples taken at center-of-mass energies from 2.00 to 3.08 GeV with the BESIII detector at the BEPCII collider, a partial wave analysis on the $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ process is performed. The Born cross sections for $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ and its intermediate processes $e^{+}e^{-}\rightarrow\rho\pi$ and $\rho(1450)\pi$ are measured as functions of $\sqrt{s}$. The results for $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ are consistent with previous results measured with the initial state radiation method within one standard deviation, and improve the uncertainty by a factor of ten. By fitting the line shapes of the Born cross sections for the $e^{+}e^{-}\rightarrow\rho\pi$ and $\rho(1450)\pi$, a structure with mass $M = 2119\pm11\pm15\ {\rm MeV}/c^2$ and width $\Gamma=69\pm30\pm5 {\rm MeV}$ is observed with a significance of $5.9\sigma$, where the first uncertainties are statistical and the second ones are systematic. This structure can be intepreteted as an excited $\omega$ state.

10.48550/arxiv.2401.14711

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Citations (1)