58 research outputs found

    Probing the nature of the χc1(3872)\chi_{c1}(3872) state using radiative decays

    No full text
    International audienceThe radiative decays χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow\psi(2S)\gamma and χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma are used to probe the~nature of the~χc1(3872)\chi_{c1}(3872) state using proton-proton collision data collected with the LHCb detector, corresponding to an~integrated luminosity of~9fb−1^{-1}. Using the~B+→χc1(3872)K+B^+\rightarrow \chi_{c1}(3872)K^+decay, the χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow \psi(2S)\gamma process is observed for the first time and the ratio of its partial width to that of the χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma decay is measured to be Γχc1(3872)→ψ(2S)ÎłÎ“Ï‡c1(3872)→J/ÏˆÎł=1.67±0.21±0.12±0.04, \frac{\Gamma_{\chi_{c1}(3872)\rightarrow \psi(2S)\gamma}} {\Gamma_{\chi_{c1}(3872)\rightarrow J/\psi\gamma}} = 1.67 \pm 0.21 \pm 0.12 \pm0.04 , where the first uncertainty is statistical, the second systematic and the third is due to the uncertainties on the branching fractions of the ψ(2S)\psi(2S) and J/ψJ/\psi mesons. The measured ratio makes the interpretation of the χc1(3872)\chi_{c1}(3872) state as a~pure D0Dˉ∗0+Dˉ0D∗0D^0\bar{D}^{*0}+\bar{D}^0D^{*0} molecule questionable and strongly indicates a sizeable compact charmonium or tetraquark component within the χc1(3872)\chi_{c1}(3872) state

    Probing the nature of the χc1(3872)\chi_{c1}(3872) state using radiative decays

    No full text
    International audienceThe radiative decays χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow\psi(2S)\gamma and χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma are used to probe the~nature of the~χc1(3872)\chi_{c1}(3872) state using proton-proton collision data collected with the LHCb detector, corresponding to an~integrated luminosity of~9fb−1^{-1}. Using the~B+→χc1(3872)K+B^+\rightarrow \chi_{c1}(3872)K^+decay, the χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow \psi(2S)\gamma process is observed for the first time and the ratio of its partial width to that of the χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma decay is measured to be Γχc1(3872)→ψ(2S)ÎłÎ“Ï‡c1(3872)→J/ÏˆÎł=1.67±0.21±0.12±0.04, \frac{\Gamma_{\chi_{c1}(3872)\rightarrow \psi(2S)\gamma}} {\Gamma_{\chi_{c1}(3872)\rightarrow J/\psi\gamma}} = 1.67 \pm 0.21 \pm 0.12 \pm0.04 , where the first uncertainty is statistical, the second systematic and the third is due to the uncertainties on the branching fractions of the ψ(2S)\psi(2S) and J/ψJ/\psi mesons. The measured ratio makes the interpretation of the χc1(3872)\chi_{c1}(3872) state as a~pure D0Dˉ∗0+Dˉ0D∗0D^0\bar{D}^{*0}+\bar{D}^0D^{*0} molecule questionable and strongly indicates a sizeable compact charmonium or tetraquark component within the χc1(3872)\chi_{c1}(3872) state

    Amplitude analysis of B+→ψ(2S)K+π+π−B^+ \to \psi(2S) K^+ \pi^+ \pi^- decays

    No full text
    International audienceThe first full amplitude analysis of B+→ψ(2S)K+π+π−B^+ \to \psi(2S) K^+ \pi^+ \pi^- decays is performed using proton-proton collision data corresponding to an integrated luminosity of 9 fb−19\,\text{fb}^{-1} recorded with the LHCb detector. The rich K+π+π−K^+ \pi^+ \pi^- spectrum is studied and the branching fractions of the resonant substructure associated with the prominent K1(1270)+K_1(1270)^+ contribution are measured. The data cannot be described by conventional strange and charmonium resonances only. An amplitude model with 53 components is developed comprising 11 hidden-charm exotic hadrons. New production mechanisms for charged charmonium-like states are observed. Significant resonant activity with spin-parity JP=1+J^P = 1^+ in the ψ(2S)π+\psi(2S) \pi^+ system is confirmed and a multi-pole structure is demonstrated. The spectral decomposition of the ψ(2S)π+π−\psi(2S) \pi^+ \pi^- invariant-mass structure, dominated by X0→ψ(2S)ρ(770)0X^0 \to \psi(2S) \rho(770)^0 decays, broadly resembles the J/ψϕJ/\psi \phi spectrum observed in B+→J/ψϕK+B^+ \to J/\psi \phi K^+ decays. Exotic ψ(2S)K+π−\psi(2S) K^+ \pi^- resonances are observed for the first time

    Amplitude analysis of B+→ψ(2S)K+π+π−B^+ \to \psi(2S) K^+ \pi^+ \pi^- decays

    No full text
    International audienceThe first full amplitude analysis of B+→ψ(2S)K+π+π−B^+ \to \psi(2S) K^+ \pi^+ \pi^- decays is performed using proton-proton collision data corresponding to an integrated luminosity of 9 fb−19\,\text{fb}^{-1} recorded with the LHCb detector. The rich K+π+π−K^+ \pi^+ \pi^- spectrum is studied and the branching fractions of the resonant substructure associated with the prominent K1(1270)+K_1(1270)^+ contribution are measured. The data cannot be described by conventional strange and charmonium resonances only. An amplitude model with 53 components is developed comprising 11 hidden-charm exotic hadrons. New production mechanisms for charged charmonium-like states are observed. Significant resonant activity with spin-parity JP=1+J^P = 1^+ in the ψ(2S)π+\psi(2S) \pi^+ system is confirmed and a multi-pole structure is demonstrated. The spectral decomposition of the ψ(2S)π+π−\psi(2S) \pi^+ \pi^- invariant-mass structure, dominated by X0→ψ(2S)ρ(770)0X^0 \to \psi(2S) \rho(770)^0 decays, broadly resembles the J/ψϕJ/\psi \phi spectrum observed in B+→J/ψϕK+B^+ \to J/\psi \phi K^+ decays. Exotic ψ(2S)K+π−\psi(2S) K^+ \pi^- resonances are observed for the first time

    Study of the rare decay J ⁣/ψ→Ό+Ό−Ό+Ό−J\mskip -3mu/\mskip -2mu\psi \to \mu^+\mu^-\mu^+\mu^-

    No full text
    The rare electromagnetic J ⁣/ψ→Ό+Ό−Ό+Ό−J\mskip -3mu/\mskip -2mu\psi \to \mu^+\mu^-\mu^+\mu^- decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016--2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−15.4\,\text{fb}^{-1}. The rate of this decay is measured relative to that of the J ⁣/ψ→Ό+Ό−J\mskip -3mu/\mskip -2mu\psi \to \mu^+\mu^- mode. Using the QED model for the four-muon decay in the efficiency estimation, its branching fraction is determined to be \begin{equation*} {\mathcal{B}}(J\mskip -3mu/\mskip -2mu\psi \to \mu^+\mu^-\mu^+\mu^-) = (1.13\pm0.10\pm0.05\pm0.01)\times 10^{-6}, \end{equation*} where the uncertainties are statistical, systematic and due to the uncertainty on the branching fraction of the J ⁣/ψ→Ό+Ό−J\mskip -3mu/\mskip -2mu\psi \to \mu^+\mu^- decay.The rare electromagnetic J/ψ→Ό+Ό−Ό+Ό−J/\psi \to \mu^+\mu^-\mu^+\mu^- decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016-2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−15.4\,\text{fb}^{-1}. The rate of this decay is measured relative to that of the J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- mode. Using the QED model for the four-muon decay in the efficiency estimation, its branching fraction is determined to be \begin{equation*} {\mathcal{B}}(J/\psi \to \mu^+\mu^-\mu^+\mu^-) = (1.13\pm0.10\pm0.05\pm0.01)\times 10^{-6}, \end{equation*} where the uncertainties are statistical, systematic and due to the uncertainty on the branching fraction of the J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- decay

    Study of the rare decay J/ψ→Ό+Ό−Ό+Ό−J/\psi \to \mu^+\mu^-\mu^+\mu^-

    No full text
    International audienceThe rare electromagnetic J/ψ→Ό+Ό−Ό+Ό−J/\psi \to \mu^+\mu^-\mu^+\mu^- decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016-2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−15.4\,\text{fb}^{-1}. The rate of this decay is measured relative to that of the J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- mode. Using the QED model for the four-muon decay in the efficiency estimation, its branching fraction is determined to be \begin{equation*} {\mathcal{B}}(J/\psi \to \mu^+\mu^-\mu^+\mu^-) = (1.13\pm0.10\pm0.05\pm0.01)\times 10^{-6}, \end{equation*} where the uncertainties are statistical, systematic and due to the uncertainty on the branching fraction of the J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- decay

    Study of the rare decay J/ψ→Ό+Ό−Ό+Ό−J/\psi \to \mu^+\mu^-\mu^+\mu^-

    No full text
    International audienceThe rare electromagnetic J/ψ→Ό+Ό−Ό+Ό−J/\psi \to \mu^+\mu^-\mu^+\mu^- decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016-2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−15.4\,\text{fb}^{-1}. The rate of this decay is measured relative to that of the J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- mode. Using the QED model for the four-muon decay in the efficiency estimation, its branching fraction is determined to be \begin{equation*} {\mathcal{B}}(J/\psi \to \mu^+\mu^-\mu^+\mu^-) = (1.13\pm0.10\pm0.05\pm0.01)\times 10^{-6}, \end{equation*} where the uncertainties are statistical, systematic and due to the uncertainty on the branching fraction of the J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- decay

    Probing the nature of the χc1(3872)\chi_{c1}(3872) state using radiative decays

    No full text
    International audienceThe radiative decays χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow\psi(2S)\gamma and χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma are used to probe the~nature of the~χc1(3872)\chi_{c1}(3872) state using proton-proton collision data collected with the LHCb detector, corresponding to an~integrated luminosity of~9fb−1^{-1}. Using the~B+→χc1(3872)K+B^+\rightarrow \chi_{c1}(3872)K^+decay, the χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow \psi(2S)\gamma process is observed for the first time and the ratio of its partial width to that of the χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma decay is measured to be Γχc1(3872)→ψ(2S)ÎłÎ“Ï‡c1(3872)→J/ÏˆÎł=1.67±0.21±0.12±0.04, \frac{\Gamma_{\chi_{c1}(3872)\rightarrow \psi(2S)\gamma}} {\Gamma_{\chi_{c1}(3872)\rightarrow J/\psi\gamma}} = 1.67 \pm 0.21 \pm 0.12 \pm0.04 , where the first uncertainty is statistical, the second systematic and the third is due to the uncertainties on the branching fractions of the ψ(2S)\psi(2S) and J/ψJ/\psi mesons. The measured ratio makes the interpretation of the χc1(3872)\chi_{c1}(3872) state as a~pure D0Dˉ∗0+Dˉ0D∗0D^0\bar{D}^{*0}+\bar{D}^0D^{*0} molecule questionable and strongly indicates a sizeable compact charmonium or tetraquark component within the χc1(3872)\chi_{c1}(3872) state

    Probing the nature of the χc1(3872)\chi_{c1}(3872) state using radiative decays

    No full text
    International audienceThe radiative decays χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow\psi(2S)\gamma and χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma are used to probe the~nature of the~χc1(3872)\chi_{c1}(3872) state using proton-proton collision data collected with the LHCb detector, corresponding to an~integrated luminosity of~9fb−1^{-1}. Using the~B+→χc1(3872)K+B^+\rightarrow \chi_{c1}(3872)K^+decay, the χc1(3872)→ψ(2S)Îł\chi_{c1}(3872)\rightarrow \psi(2S)\gamma process is observed for the first time and the ratio of its partial width to that of the χc1(3872)→J/ÏˆÎł\chi_{c1}(3872)\rightarrow J/\psi\gamma decay is measured to be Γχc1(3872)→ψ(2S)ÎłÎ“Ï‡c1(3872)→J/ÏˆÎł=1.67±0.21±0.12±0.04, \frac{\Gamma_{\chi_{c1}(3872)\rightarrow \psi(2S)\gamma}} {\Gamma_{\chi_{c1}(3872)\rightarrow J/\psi\gamma}} = 1.67 \pm 0.21 \pm 0.12 \pm0.04 , where the first uncertainty is statistical, the second systematic and the third is due to the uncertainties on the branching fractions of the ψ(2S)\psi(2S) and J/ψJ/\psi mesons. The measured ratio makes the interpretation of the χc1(3872)\chi_{c1}(3872) state as a~pure D0Dˉ∗0+Dˉ0D∗0D^0\bar{D}^{*0}+\bar{D}^0D^{*0} molecule questionable and strongly indicates a sizeable compact charmonium or tetraquark component within the χc1(3872)\chi_{c1}(3872) state

    Amplitude analysis of B+→ψ(2S)K+π+π−B^+ \to \psi(2S) K^+ \pi^+ \pi^- decays

    No full text
    International audienceThe first full amplitude analysis of B+→ψ(2S)K+π+π−B^+ \to \psi(2S) K^+ \pi^+ \pi^- decays is performed using proton-proton collision data corresponding to an integrated luminosity of 9 fb−19\,\text{fb}^{-1} recorded with the LHCb detector. The rich K+π+π−K^+ \pi^+ \pi^- spectrum is studied and the branching fractions of the resonant substructure associated with the prominent K1(1270)+K_1(1270)^+ contribution are measured. The data cannot be described by conventional strange and charmonium resonances only. An amplitude model with 53 components is developed comprising 11 hidden-charm exotic hadrons. New production mechanisms for charged charmonium-like states are observed. Significant resonant activity with spin-parity JP=1+J^P = 1^+ in the ψ(2S)π+\psi(2S) \pi^+ system is confirmed and a multi-pole structure is demonstrated. The spectral decomposition of the ψ(2S)π+π−\psi(2S) \pi^+ \pi^- invariant-mass structure, dominated by X0→ψ(2S)ρ(770)0X^0 \to \psi(2S) \rho(770)^0 decays, broadly resembles the J/ψϕJ/\psi \phi spectrum observed in B+→J/ψϕK+B^+ \to J/\psi \phi K^+ decays. Exotic ψ(2S)K+π−\psi(2S) K^+ \pi^- resonances are observed for the first time
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