Strong decays of low-lying DD-wave Ξb/Ξb′\Xi_b/\Xi_b' baryons with QPC model

For further decoding the inner structure of the two excited $\Xi_b$ states observed by LHCb, we perform a systematical study of the strong decays of the low-lying $1D$-wave $\Xi_b$ and $\Xi_b'$ excitations using the quark pair creation model within the $j-j$ coupling scheme. Combining with the measured masses and decay properties of $\Xi_{b}(6327)^{0}$ and $\Xi_{b}(6327)^{0}$, the two excited states can be explained as $1D$ $\lambda$-mode $\Xi_b$ states $\Xi_{b}|J^{P}=\frac{3}{2}^{+},2\rangle_{\lambda\lambda}$ and $\Xi_{b}|J^{P}=\frac{5}{2}^{+},2\rangle_{\lambda\lambda}$, respectively. If such a view were correct, $\Xi_b'\pi$ and $\Xi_b'^*\pi$ could be another interesting channels for experimental exploring of the $\Xi_{b}(6327)^{0}$ and $\Xi_{b}(6327)^{0}$, respectively. Those calculations are good consistent with the results within the chiral quark model. In addition, for the other missing $1D$-wave $\Xi_b$ and $\Xi_b'$ excitations, our predictions indicate that:(i) the two $\rho$-mode $1D$ $\Xi_b$ states are likely to be moderate states with a width of $\Gamma\sim50$ MeV. The $J^P=3/2^+$ state dominantly decays into $\Sigma_bK$ and $\Xi_b'\pi$, while the $J^P=5/2^+$ state decays primarily through $\Sigma_b^*K$ and $\Xi_b'^*\pi$. (ii) The $\lambda$-mode $1D$ $\Xi_b'$ states may be moderate states with a widths of about several to dozens of MeV. Most of the $\lambda$-mode $1D$ $\Xi_b'$ states mainly decay into the $1P$-wave bottomed baryon via the pionic decay processes. Meanwhile, several $\lambda$-mode $1D$ $\Xi_b'$ states have significant decay rates into $\Lambda B$. (iii) While, the $\rho$-mode $1D$ $\Xi_b'$ states are predicted to be very broad states with a width of about several hundreds MeV. It will be a great challenge to explore the $\rho$-mode $1D$ $\Xi_b'$ states in experiments for their broad widths.Comment: 11 pages, 5 figure

Life fingerprints of nuclear reactions in the body of animals

Nuclear reactions are a very important natural phenomenon in the universe. On the earth, cosmic rays constantly cause nuclear reactions. High energy beams created by medical devices also induce nuclear reactions in the human body. The biological role of these nuclear reactions is unknown. Here we show that the in vivo biological systems are exquisite and sophisticated by nature in influence on nuclear reactions and in resistance to radical damage in the body of live animals. In this study, photonuclear reactions in the body of live or dead animals were induced with 50-MeV irradiation. Tissue nuclear reactions were detected by positron emission tomography (PET) imaging of the induced beta+ activity. We found the unique tissue "fingerprints" of beta+ (the tremendous difference in beta+ activities and tissue distribution patterns among the individuals) are imprinted in all live animals. Within any individual, the tissue "fingerprints" of 15O and 11C are also very different. When the animal dies, the tissue "fingerprints" are lost. The biochemical, rather than physical, mechanisms could play a critical role in the phenomenon of tissue "fingerprints". Radiolytic radical attack caused millions-fold increases in 15O and 11C activities via different biochemical mechanisms, i.e. radical-mediated hydroxylation and peroxidation respectively, and more importantly the bio-molecular functions (such as the chemical reactivity and the solvent accessibility to radicals). In practice biologically for example, radical attack can therefore be imaged in vivo in live animals and humans using PET for life science research, disease prevention, and personalized radiation therapy based on an individual's bio-molecular response to ionizing radiation

Strong decays of the low-lying 1P1P- and 1D1D-wave Σc\Sigma_c baryons

In this work, we systematically study the OZI-allowed two-body strong decay properties of $1P$- and $1D$-wave $\Sigma_c$ baryons within the $j$-$j$ coupling scheme in the framework of the quark pair creation model. For a comparison, we also give the predictions of the chiral quark model. Some model dependencies can be found in the predictions of two models. The calculations indicate that: (i) The $1P$-wave $\lambda$-mode $\Sigma_c$ states most likely to be relatively narrow states with a width of $\Gamma<80$ MeV. Their main decay channels are $\Lambda_c\pi$, or $\Sigma_c\pi$, or $\Sigma_c^*\pi$. The $1P$-wave $\rho$-mode states most might be broad states with a width of $\Gamma\sim 100-200$ MeV. They dominantly decay into $\Sigma_c\pi$ and $\Sigma_c^*\pi$ channels. Some evidences of these $1P$-wave states are most likely to be observed in the $\Lambda_c\pi$ and $\Lambda_c\pi\pi$ invariant mass spectra around the energy range of $2.75-2.95$ GeV. (ii) The $1D$-wave $\lambda$-mode $\Sigma_c$ excitations may be moderate states with a width of about dozens of MeV. The $1D$-wave $\lambda$-mode states mainly decay into the $1P$-wave charmed baryon via the pionic decay processes. Meanwhile, several $1D$-wave $\lambda$-mode states have significant decay rates into $DN$ or $D^*N$. Hence, the $DN$ and $D^*N$ are likely to be interesting channels for experimental exploration. (iii) Furthermore, the two $1D$-wave $\rho$-mode excitations $\Sigma_c|J^P=5/2^+,3\rangle_{\rho\rho}$ and $|J^P=7/2^+,3\rangle_{\rho\rho}$ are most likely to be fairly narrow state with a width of dozens of MeV, and they mainly decay into $\Lambda_c\pi$. Some evidences of them might be observed in the $\Lambda_c\pi$ invariant mass spectra around the energy range of $3.1-3.2$ GeV.Comment: 12 pages,5 figures, 4 tables. arXiv admin note: text overlap with arXiv:2208.1011

Geometry and optics calibration of WFCTA prototype telescopes using star light

The Large High Altitude Air Shower Observatory project is proposed to study high energy gamma ray astronomy ( 40 GeV-1 PeV ) and cosmic ray physics ( 20 TeV-1 EeV ). The wide field of view Cherenkov telescope array, as a component of the LHAASO project, will be used to study energy spectrum and compositions of cosmic ray by measuring the total Cherenkov light generated by air showers and shower maximum depth. Two prototype telescopes have been in operation since 2008. The pointing accuracy of each telescope is crucial to the direction reconstruction of the primary particles. On the other hand the primary energy reconstruction relies on the shape of the Cherenkov image on the camera and the unrecorded photons due to the imperfect connections between photomultiplier tubes. UV bright stars are used as point-like objects to calibrate the pointing and to study the optical properties of the camera, the spot size and the fractions of unrecorded photons in the insensitive areas of the camera.Comment: 5 pages, 6 figures, submitted to Chinese Physics