关键词：
B physics;Branching fraction;CP violation;Flavor physics;Hadron-Hadron scattering (experiments)
摘要：
The fi rst untagged decay-time-integrated amplitude analysis of B 0 s ! K 0 S K decays is performed using a sample corresponding to 3: 0 fb of pp collision data recorded with the LHCb detector during 2011 and 2012. The data are described with an amplitude model that contains contributions from the intermediate resonances K 9892) 0;+, K 2 91430) 0;+ and K 0 91430) 0;+, and their charge conjugates. Measurements of the branching fractions of the decay modes B 0 s ! K 9892) K and B 0 s ! K 9892) 0 K 0 are in agreement with, and more precise than, previous results. The decays B 0 s ! K 0 91430) K and B 0 s ! K 0 91430) 0 K 0 are observed for the fi rst time, each with signi fi cance over 10 standard deviations.
摘要：
The production of charged hadrons within jets recoiling against a Z boson is measured in proton-proton collision data at sqrt[s]=8 TeV recorded by the LHCb experiment. The charged-hadron structure of the jet is studied longitudinally and transverse to the jet axis for jets with transverse momentum p_{T}>20 GeV and in the pseudorapidity range 2.5<eta<4. These are the first measurements of jet hadronization at these forward rapidities and also the first where the jet is produced in association with a Z boson. In contrast to previous hadronization measurements at the Large Hadron Collider, which are dominated by gluon jets, these measurements probe predominantly light-quark jets which are found to be more longitudinally and transversely collimated with respect to the jet axis when compared to the previous gluon dominated measurements. Therefore, these results provide valuable information on differences between quarks and gluons regarding nonperturbative hadronization dynamics.
作者：
Aaij, R.;Abellan Beteta, C.;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
Journal of High Energy Physics,2019年2019(7):1-23 ISSN：1029-8479
通讯作者：
Belyaev, I.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; de Vries, J. A.; Veronesi, M.; Aaij, R.; Greim, R.; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Archilli, F.; van Veghel, M.; Koppenburg, P.; Gras, C. Sanchez; Raven, G.; Sierra, C. Vazquez; Pajero, T.; Ferreres Sole, S.; Govorkova, E.; Kostiuk, I.; Benson, S.; Hulsbergen, W.] Nikhef, Natl Inst Subat Phys, Amsterdam, Netherlands.;[Tourinho Jadallah Aoude, R.; Massafferri, A.; De Miranda, J. M.; Soares Lavra, L.; Gomes, A.; Bediaga, I.; dos Reis, A. C.] CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Otalora Goicochea, J. M.; Carvalho Akiba, K.; Silva de Oliveira, L.; De Paula, L.; Nasteva, I.; Amato, S.] Univ Fed Rio de Janeiro, UFRJ, Rio De Janeiro, Brazil.;[Gao, Y.; Yang, Z.; Jiang, F.; Xu, A.; Ren, Z.; Tang, Z.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Chen, C.; Zhu, X.; Luo, Y.; Zeng, M.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Beliy, N.; Lyu, X.; Szymanski, M.; Xu, Q.; Huang, W.; Li, P. -R.; He, J.; Saur, M.; Qian, W.; Qin, J.; Zheng, Y.; Vieira, D.] Univ Chinese Acad Sci, Beijing, Peoples R China.
通讯机构：
[Belyaev, I.] N;NRC KI, ITEP, Moscow, Russia.
摘要：
Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector between 2011 and 2018, a new narrow charmonium state, the X(3842) resonance, is observed in the decay modes
$$ \mathrm{X}(3842)\to {D}^0{\overline{D}}^0 $$
and X(3842) → D+D−. The mass and the natural width of this state are measured to be
$$ \begin{array}{l}{m}_{X(3842)}=3842.71\pm 0.16\pm 0.12\ MeV/{c}^2,\hfill \\ {}{\varGamma}_{X(3842)}=2.79\pm 0.51\pm 0.35\ MeV,\hfill \end{array} $$
where the first uncertainty is statistical and the second is systematic. The observed mass and narrow natural width suggest the interpretation of the new state as the unobserved (spin-3 ψ3 13D3) charmonium state. In addition, prompt hadroproduction of the ψ(3770) and χ2(3930) states is observed for the first time, and the parameters of these states are measured to be
$$ \begin{array}{l}{m}_{\psi (3770)}=3778.1\pm 0.7\pm 0.6\ MeV/{c}^2,\hfill \\ {}{m}_{\chi_2(3930)}=3921.9\pm 0.6\pm 0.2\ MeV/{c}^2,\hfill \\ {}{\varGamma}_{\chi_2(3930)}=36.6 \pm 1.9 \pm 0.9\ MeV,\hfill \end{array} $$
where the first uncertainty is statistical and the second is systematic.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; de Vries, J. A.; Veronesi, M.; Aaij, R.; Greim, R.; van Beuzekom, M.; Dufour, L.; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Archilli, F.; van Veghel, M.; Koppenburg, P.; Gras, C. Sanchez; Raven, G.; Sierra, C. Vazquez; Govorkova, E.; Kostiuk, I.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Tourinho Jadallah Aoude, R.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Soares Lavra, L.; Gomes, A.; Bediaga, I.; dos Reis, A. C.] CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Otalora Goicochea, J. M.; Carvalho Akiba, K.; Silva de Oliveira, L.; De Paula, L.; Nasteva, I.; Da Cunha Marinho, F.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Gao, Y.; Yang, Z.; Jiang, F.; Xu, A.; Ren, Z.; Tang, Z.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Chen, C.; Zhu, X.; Davis, A.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Li, Y.; Zhang, Y.; Wang, J.] Ihep, Beijing, Peoples R China.
通讯机构：
[Vieites Diaz, M.] U;Univ Santiago de Compostela, IGFAE, Santiago De Compostela, Spain.
摘要：
The first amplitude analysis of the B^{+/-}-->pi^{+/-}K^{+}K^{-} decay is reported based on a data sample corresponding to an integrated luminosity of 3.0 fb^{-1} of pp collisions recorded in 2011 and 2012 with the LHCb detector. The data are found to be best described by a coherent sum of five resonant structures plus a nonresonant component and a contribution from pipi<-->KK S-wave rescattering. The dominant contributions in the pi^{+/-} K^{-/+} and K^{+} K^{-} systems are the nonresonant and the B^{+/-}-->rho(1450)^{0}pi^{+/-} amplitudes, respectively, with fit fractions around 30%. For the rescattering contribution, a sizable fit fraction is observed. This component has the largest CP asymmetry reported to date for a single amplitude of (-66+/-4+/-2)%, where the first uncertainty is statistical and the second systematic. No significant CP violation is observed in the other contributions.
关键词：
B physics;Branching fraction;Flavor physics;Hadron-Hadron scattering (experiments)
摘要：
Using pp collisions corresponding to 3 fb integrated luminosity, recorded by the LHCb experiment at centre- of- mass energies of 7 and 8TeV, the ratio of branching fractions B (0b ! (2 S) ) =B (0b ! J= ) = 0 : 513 0 : 023 (stat) 0 : 016 (syst) 0 : 011 (B) is determined. The fi rst uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; de Vries, J. A.; Veronesi, M.; Aaij, R.; Greim, R.; van Beuzekom, M.; Dufour, L.; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Archilli, F.; van Veghel, M.; Koppenburg, P.; Gras, C. Sanchez; Raven, G.; Sierra, C. Vazquez; Govorkova, E.; Kostiuk, I.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Tourinho Jadallah Aoude, R.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Soares Lavra, L.; Gomes, A.; Bediaga, I.; dos Reis, A. C.] CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Otalora Goicochea, J. M.; Carvalho Akiba, K.; Silva de Oliveira, L.; De Paula, L.; Nasteva, I.; Da Cunha Marinho, F.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Gao, Y.; Yang, Z.; Jiang, F.; Xu, A.; Ren, Z.; Tang, Z.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Chen, C.; Zhu, X.; Davis, A.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Li, Y.; Zhang, Y.; Wang, J.] Ihep, Beijing, Peoples R China.
通讯机构：
[Vieites Diaz, M.] U;Univ Santiago de Compostela, IGFAE, Santiago De Compostela, Spain.
摘要：
A tunable terahertz quintuple-band metamaterial graphene absorber is presented in this paper. The designed absorber consists of single-layered graphene and a gold bottom plane separated by a dielectric layer. The simulation results show that the absorber has high absorption in five frequency bands of 0.93 THz, 1.72 THz, 2.39 THz, 3.05 THz and 3.72 THz with the absorption of 99.9%, 99.7%, 96.4%, 94.7% and 92.9%, respectively. Beyond that, the polarization sensitivity of the absorber is not obvious, and the incident range is large under both transverse-electric and transverse-magnetic waves. By changing the Fermi energy of graphene from 0 eV to 1.0 eV, the absorption can be flexibly changed from 20% to 100%, which opens up the possibility of graphene-based tunable devices.
关键词：
Performance of High Energy Physics Detectors;Trigger concepts and systems (hardware and software);Large detector-systems performance;Trigger algorithms
摘要：
The LHCb collaboration has redesigned its trigger to enable the full offline detector reconstruction to be performed in real time. Together with the real-time alignment and calibration of the detector, and a software infrastructure to make persistent the high-level physics objects produced during real-time processing, this redesign enabled the widespread deployment of real-time analysis during Run 2. We describe the design of the Run 2 trigger and real-time reconstruction, and present data-driven performance measurements for a representative sample of LHCb's physics programme.
期刊：
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT,2019年924:82-86 ISSN：0168-9002
通讯作者：
Zhang, Ying
作者机构：
[Huang, Guangming; Xiao, Le; Zhang, Li; Li, Yashu; Zhou, Wei; Yang, Ping; Ren, Weiping; Sun, Xiangming; Liu, Jianchao; You, Bihui; Gao, Chaosong; Liu, Jun; Huang, Xing] Cent China Normal Univ, PLAC, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.;[Zhang, Ying] State Key Lab Particle Detect & Elect, Beijing 100049, Peoples R China.;[Zhang, Ying] Inst High Energy Phys, 19B YuquanLu, Beijing 100049, Peoples R China.
通讯机构：
[Zhang, Ying] I;Inst High Energy Phys, 19B YuquanLu, Beijing 100049, Peoples R China.
会议名称：
11th International Hiroshima Symposium on the Development and Application of Semiconductor Tracking Detectors (HSTD) in conjunction with 2nd Workshop on SOI Pixel Detector (SOIPIX)
会议时间：
DEC 11-15, 2017
会议地点：
Okinawa Inst sci & Technol Grad Univ, Okinawa, JAPAN
会议主办单位：
Okinawa Inst sci & Technol Grad Univ
关键词：
Monolithic Active Pixel Sensor (MAPS);In-matrix zero-suppression;Vertex detector;CEPC
摘要：
The Circular Electron Positron Collider (CEPC) is proposed as a Higgs factory for precision measurement of properties of the Higgs boson. The CEPC vertex detector requires low material budget, high spatial resolution, fast readout and low power consumption. Monolithic Active Pixel Sensor (MAPS), as one of the promising candidate technologies, has been studied within the R&D activities for the CEPC vertex detector. This proceeding introduces recent development of a MAPS prototype using the TowerJazz 180 nm CMOS Image Sensor process. Two different binary front-end circuits have been designed to explore an in-pixel front-end structure suitable for a compact pixel in combination with an in-matrix sparsified readout circuitry. To achieve high granularity together with fast readout speed, a new architecture of asynchronous data-driven matrix readout has been implemented. The prototype contains 128 rows and 64 columns featuring a small pixel pitch of 25 mu m. The address of one hit pixel can be read out in 25 ns. This work presents the design of the prototype, which is currently under test.
摘要：
Wire-shaped asymmetric pseudocapacitors with both pseudocapacitive cathode and anode are promising in facilitating device assembly and provide highly efficient power sources for wearable electronics. However, it is a great challenge to simultaneously obtain high energy and power as well as ultralong cycling life for practical demands of such devices. Herein, a device design with new cathode/anode coupling is proposed to achieve excellent comprehensive performance in a wire-type quasi-solid-state asymmetric pseudocapacitor (WQAP). The hierarchical alpha-MnO2 nanorod@delta-MnO2 nanosheet array cathode and MoO2@C nanofilm anode are directly grown on flexible tiny Ti wires by well-established hydrothermal and electrodeposition techniques, which ensures rapid charge/mass transport kinetics and the sufficient utilization of pseudocapacitance. The nanoarray/film electrode also facilitates integration with gel electrolyte of polyvinyl alcohol-LiCl, guaranteeing the durability. The resulting WQAP with 2.0 V voltage delivers high volumetric energy and power densities (9.53 mWh cm(-3) and 22720 mW cm(-3), respectively) as well as outstanding cycling stability over 100 000 times, surpassing all the previously reported WQAPs. In addition, the device can be facilely connected in parallel or in series with minimal internal resistance, and be fabricated at the 1 m scale with excellent flexibility. This work opens the way to develop high-performance integrated wire supercapacitors.
作者：
Aaij, R.;Beteta, C. Abellan;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
EUROPEAN PHYSICAL JOURNAL C,2019年79(8):1-12 ISSN：1434-6044
通讯作者：
Stefkova, S.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; de Vries, J. A.; Veronesi, M.; Aaij, R.; Greim, R.; van Beuzekom, M.; Dufour, L.; Feo, M.; Kostiuk, I; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Archilli, F.; van Veghel, M.; Koppenburg, P.; Gras, C. Sanchez; Raven, G.; Sierra, C. Vazquez; Govorkova, E.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Tourinho Jadallah Aoude, R.; Massafferri, A.; De Miranda, J. M.; Soares Lavra, L.; Torres, M. Cruz; Gomes, A.; dos Reis, A. C.; Bediaga, I] CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Nasteva, I; Otalora Goicochea, J. M.; Carvalho Akiba, K.; Potterat, C.; Silva de Oliveira, L.; De Paula, L.; Da Cunha Marinho, F.; Amato, S.] Univ Fed Rio de Janeiro, Rio de Janeiro, Brazil.;[Gao, Y.; Yang, Z.; Jiang, F.; Xu, A.; Ren, Z.; Tang, Z.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Chen, C.; Zhu, X.; An, L.; Davis, A.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Beliy, N.; Li, P-R; Lyu, X.; Szymanski, M.; Xu, Q.; Huang, W.; He, J.; Saur, M.; Qian, W.; Qin, J.; Zheng, Y.; Vieira, D.] Univ Chinese Acad Sci, Beijing, Peoples R China.
作者：
Aaij, R.;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
EUROPEAN PHYSICAL JOURNAL C,2019年79(8):1-26 ISSN：1434-6044
通讯作者：
Dordei, F.;Chobanova, V.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; Kuindersma, H. S.; de Vries, J. A.; Heijhoff, K.; Beuzekom, M. van; Veronesi, M.; Aaij, R.; Greim, R.; Martinez, M. Lucio; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Butter, J. S.; Koppenburg, P.; Tilburg, J. van; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Kostiuk, I.; Schubiger, M.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Torres, M. Cruz; Gomes, A.; Lavra, L. Soares; Bediaga, I.; Reis, A. C. dos] Ctr Brasileiro Pesquisas Fisicas CBPF, Rio De Janeiro, Brazil.;[De Paula, B. Souza; de Oliveira, L. Silva; Lopes, J. H.; Goicochea, J. M. Otalora; Polycarpo, E.; Gandelman, M.; Rangel, M. S.; Rodrigues, F. Ferreira; Akiba, K. Carvalho; De Paula, L.; Nasteva, I.; Amato, S.] Univ Fed Rio Janeiro UFRJ, Rio De Janeiro, Brazil.;[Gao, Y.; Yang, Z.; Zhang, S.; Jiang, F.; Fan, J.; Xu, A.; Ren, Z.; Xu, L.; Tang, Z.; Wang, J.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Chen, C.; Zhu, X.; Luo, Y.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Li, Y.; Wang, J.; Tobin, M.] Inst High Energy Phys ihep, Beijing, Peoples R China.
通讯机构：
[Dordei, F.] I;[Chobanova, V.] U;INFN, Sez Pisa, Pisa, Italy.;Univ Santiago de Compostela, IGFAE, Santiago De Compostela, Spain.
摘要：
The decay-time-dependent $$CP$$ asymmetry in $${{B} ^0_{s}} \rightarrow J/\psi {{K} ^+} {{K} ^-} $$ decays is measured using proton–proton collision data, corresponding to an integrated luminosity of $$1.9\,\mathrm{fb}^{-1} $$, collected with the LHCb detector at a centre-of-mass energy of $$13\,\mathrm {TeV}$$ in 2015 and 2016. Using a sample of approximately 117000 signal decays with an invariant $${{K} ^+} {{K} ^-} $$ mass in the vicinity of the $$\phi (1020)$$ resonance, the $$CP$$-violating phase $$\phi _s$$ is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $${{B} ^0_{s}} $$-$${{\overline{B}{}} {}^0_{s}} $$ system, $$\Delta \Gamma _s$$. The difference of the average $${{B} ^0_{s}} $$ and $${{B} ^0} $$ meson decay widths, $$\Gamma _s-\Gamma _d$$, is determined using in addition a sample of $${{B} ^0} \rightarrow J/\psi {{K} ^+} {{\pi } ^-} $$ decays. The values obtained are $$\phi _s = -0.083\pm 0.041\pm 0.006\mathrm { \,rad} $$, $$\Delta \Gamma _s = 0.077 \pm 0.008 \pm 0.003 {\mathrm { \,ps^{-1}}} $$ and $$\Gamma _s-\Gamma _d = -0.0041 \pm 0.0024 \pm 0.0015{\mathrm { \,ps^{-1}}} $$, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of these quantities to date and are consistent with expectations based on the Standard Model and with a previous LHCb analysis of this decay using data recorded at centre-of-mass energies 7 and 8 TeV. Finally, the results are combined with recent results from $${{B} ^0_{s}} \rightarrow J/\psi {{\pi } ^+} {{\pi } ^-} $$ decays obtained using the same dataset as this analysis, and with previous independent LHCb results.
摘要：
Exploring the accurate structure ensembles are critical to understand the functions of intrinsically disordered proteins (IDPs). As a well-known IDP, islet amyloid polypeptide (IAPP) plays important roles in the development of human type II diabetes (T2D). The toxicity of human IAPP (hIAPP) is induced by the amyloidosis of the peptide, however, its aggregation mechanism remains ambiguous. The characterization of structure ensemble of hIAPP, as well as the differences between hIAPP and its non-amyloidogenic homologous such as rat IAPP (rIAPP), would greatly help to illuminate the amyloidosis mechanism of IAPP. In this study, the atomic structure ensembles of hIAPP and rIAPP were characterized by all-atom molecular dynamics (MD) simulations combined with enhanced sampling technology and experiment data restraints. The obtained structure ensembles were firstly compared with those determined by the conventional MD (cMD) and enhanced sampling without experiment data restraints. The results showed that the enhanced sampling and experiment data restraints would improve the simulation accuracy. The transient N-terminal alpha-helix structures were adopted by the sub-states of both hIAPP and rIAPP, however, the C-terminal helical structures were only present on hIAPP. The hydrophobic residues in the amyloid-core region of hIAPP are exposed to the solvent. The structure ensemble differences between hIAPP and rIAPP revealed in this work provide potential explain to the amyloidogenic mechanism and would be helpful for the design of drugs to combat T2D.
作者：
Aaij, R.;Beteta, C. Abellan;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
Journal of High Energy Physics,2019年2019(9):1-20 ISSN：1029-8479
通讯作者：
Belyaev, I.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; de Vries, J. A.; Veronesi, M.; Aaij, R.; Greim, R.; van Beuzekom, M.; Dufour, L.; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Archilli, F.; van Veghel, M.; Koppenburg, P.; Gras, C. Sanchez; Raven, G.; Sierra, C. Vazquez; Govorkova, E.; Kostiuk, I.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Tourinho Jadallah Aoude, R.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Soares Lavra, L.; Gomes, A.; Bediaga, I.; dos Reis, A. C.] CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Otalora Goicochea, J. M.; Carvalho Akiba, K.; Silva de Oliveira, L.; De Paula, L.; Nasteva, I.; Da Cunha Marinho, F.; Amato, S.] Univ Fed Rio De Janeiro UFRJ, Rio De Janeiro, Brazil.;[Gao, Y.; Yang, Z.; Jiang, F.; Xu, A.; Ren, Z.; Tang, Z.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Chen, C.; Zhu, X.; Davis, A.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Li, Y.; Zhang, Y.; Wang, J.] Ihep, Beijing, Peoples R China.
通讯机构：
[Belyaev, I.] I;ITEP, NRC KI, Moscow, Russia.
关键词：
B physics;Branching fraction;Exotics;Hadron-Hadron scattering (experiments)
摘要：
Using proton-proton collision data, collected with the LHCb detector and corresponding to 1.0, 2.0 and 1.9 fb−1 of integrated luminosity at the centre-of-mass energies of 7, 8, and 13 TeV, respectively, the decay
$$ {\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1} $$
(3872)pK− with χc1(3872) → J/ψ π+π− is observed for the first time. The significance of the observed signal is in excess of seven standard deviations. It is found that (58 ± 15)% of the decays proceed via the two-body intermediate state χc1(3872)Λ(1520). The branching fraction with respect to that of the
$$ {\Lambda}_{\mathrm{b}}^0 $$
→ ψ(2S)pK− decay mode, where the ψ(2S) meson is reconstructed in the J/ψ π+π− final state, is measured to be:
$$ \frac{\beta \left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1}(3872){\mathrm{pK}}^{-}\right)}{\beta \left({\Lambda}_{\mathrm{b}}^0\to \uppsi \left(2\mathrm{S}\right){\mathrm{pK}}^{-}\right)}\times \frac{\beta \left({\upchi}_{\mathrm{c}1}(3872)\to \mathrm{J}/\uppsi {\uppi}^{+}{\uppi}^{-}\right)}{\beta \left(\uppsi \left(2\mathrm{S}\right)\to \mathrm{J}/\uppsi {\uppi}^{+}{\uppi}^{-}\right)}=\left(5.4\pm 1.1\pm 0.2\right)\times {10}^{-2}, $$
where the first uncertainty is statistical and the second is systematic.
