论文标题
要澄清观察LHCB隐藏链的可能性，$ p_ {c}^+（4312）$，$ p_ {c}^+（4337）$，$ p_ {c}^+（4440）$和$ p_ {c}^+（c}^+（car）
Towards clarifying the possibility of observation of the LHCb hidden-charm pentaquarks $P_{c}^+(4312)$, $P_{c}^+(4337)$, $P_{c}^+(4440)$ and $P_{c}^+(4457)$ in near-threshold charmonium photoproduction off protons and nuclei
论文作者
论文摘要
我们通过考虑不连贯的直接非共振（$γp\ to {j/ψ} p $，$γn\ to {j/ψ} n $）和两步resonant（$γp\ to p _ p_i} p _ p _ p _ p _ { $γn\ to p_ {ci}^0 \ to {j/ψ} n $，$ i = 1 $，2，3，4; $ p_ {c3}^{+，0} = p_c^{+，0}（4440）$，$ p_ {c4}^{+，0} = p_c^{+，0}（4457）$）我们计算非谐振，共振剂的绝对激发函数，能量和动量分布，以及使用核光谱函数方法以及在核谱函数方法上，在碳和tungsten target上使用近晶体型核的核光谱函数方法，通过近晶体式核与近距离thres hold thres hold thers photon endive res-respartion-sidecrions-Parry sy-spartition-spartive sy-spartity- $ p_ {c}^{+，0}（4312）$，$ p_ {c}^{+，0}（4337）$，$ p_ {c}^{+，0}（4440）（4440）$和$ p_ {c} $ j^p =（1/2）^ - $，$ j^p =（1/2）^ - $和$ j^p =（3/2）^ - $在三种不同的现实场景中，对于它们衰减的分支比率与$ {j/ψ} p $和$ {j/ψ} p $和$ {j/ψ} n $ modes（0.25，0.25，0.5，0.5，0.5和1％）。我们表明，很难通过扫描$ j/ψ$的$ p_ {ci}^+$ pentaquark的状态，$ j/ψ$ potoproduction crots截面在质子近阈值的能量区域的蛋白质目标截止性区域周围的谐振光子能量周围是9.44，9.554，9.554，9.554，10.04，10.04，10.04和10.12 $ 1％，如果这些分支$ 1％和$ 1％。我们还证明，在这些光子光束上，$ j/ψ$能量和动量组合分布分别分别揭示了对上述方案的明显敏感性，以“低” $ j/ψ$总能量和动量，这意味着它们可能是为pentaquark $ p_ p_ p_ p_ p_ p_ p_ p_ con} $ p _ $ p _ $ p _ $ p _ $ p _^$ p _ $ p _^^$ p _^^^^$ pection提供进一步的证据。
We study the near-threshold $J/ψ$ meson photoproduction from protons and nuclei by considering incoherent direct non-resonant ($γp \to {J/ψ}p$, $γn \to {J/ψ}n$) and two-step resonant ($γp \to P_{ci}^+ \to {J/ψ}p$, $γn \to P_{ci}^0 \to {J/ψ}n$, $i=1$, 2, 3, 4; $P_{c1}^{+,0}=P_c^{+,0}(4312)$, $P_{c2}^{+,0}=P_c^{+,0}(4337)$, $P_{c3}^{+,0}=P_c^{+,0}(4440)$, $P_{c4}^{+,0}=P_c^{+,0}(4457)$) charmonium production processes. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of $J/ψ$ mesons on protons as well as, using the nuclear spectral function approach, on carbon and tungsten target nuclei at near-threshold incident photon energies by assuming the spin-parity assignments of the hidden-charm resonances $P_{c}^{+,0}(4312)$, $P_{c}^{+,0}(4337)$, $P_{c}^{+,0}(4440)$ and $P_{c}^{+,0}(4457)$ as $J^P=(1/2)^-$, $J^P=(1/2)^-$, $J^P=(1/2)^-$ and $J^P=(3/2)^-$ within three different realistic scenarios for the branching ratios of their decays to the ${J/ψ}p$ and ${J/ψ}n$ modes (0.25, 0.5 and 1%). We show that will be very hard to measure the $P_{ci}^+$ pentaquark states through the scan of the $J/ψ$ total photoproduction cross section on a proton target in the near-threshold energy region around the resonant photon energies of 9.44, 9.554, 10.04 and 10.12 GeV if these branching ratios $\sim$ 1% and less. We also demonstrate that at these photon beam energies the $J/ψ$ energy and momentum combined distributions considered reveal distinct sensitivity to the above scenarios, respectively, at "low" $J/ψ$ total energies and momenta, which implies that they may be an important tool to provide further evidence for the existence of the pentaquark $P_{ci}^+$ and $P_{ci}^0$ resonances.
