作者：
Aaij, R.;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
Journal of High Energy Physics,2020年2020(3):1-28 ISSN：1029-8479
通讯作者：
Vecchi, S.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; Hart, R.; Kuindersma, H. S.; de Vries, J. A.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Bel, L. J.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Onderwater, C. J. G.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Gomes, A.; Lavra, L. Soares; dos Reis, A. C.; Bediaga, I] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Nasteva, I; Sellam, S.; Otalora Goicochea, J. M.; Goebel, C.; Silva de Oliveira, L.; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Yang, Z.; Cai, H.; Zhang, S.; Jiang, F.; Fan, J.; Xu, A.; Liu, G.; Ren, Z.; Xu, L.; Tang, Z.; Li, H.; Wang, J.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Xing, H.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Gao, Y.] Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China.
关键词：
B physics;CP violation;Electroweak interaction;Flavor physics;Hadron- Hadron scattering (experiments)
摘要：
The decay-time-dependent CP asymmetry in B0 → D∗±D∓ decays is mea- sured using a data set corresponding to an integrated luminosity of 9 fb−1 recorded by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The CP parameters are measured as
$$ {\displaystyle \begin{array}{c}{S}_{D\ast D}=-0.861\pm 0.077\left(\mathrm{stat}\right)\pm 0.019\left(\mathrm{syst}\right),\\ {}\varDelta {S}_{D\ast D}=0.019\pm 0.075\left(\mathrm{stat}\right)\pm 0.012\left(\mathrm{syst}\right),\\ {}{C}_{D\ast D}=-0.059\pm 0.092\left(\mathrm{stat}\right)\pm 0.020\left(\mathrm{syst}\right),\\ {}{\varDelta C}_{D\ast D}=-0.031\pm 0.092\left(\mathrm{stat}\right)\pm 0.016\left(\mathrm{syst}\right),\\ {}{\mathcal{A}}_{D\ast D}=\kern0.75em 0.008\pm 0.014\left(\mathrm{stat}\right)\pm 0.006\left(\mathrm{syst}\right).\end{array}} $$
The analysis provides the most precise single measurement of CP violation in this decay channel to date. All parameters are consistent with their current world average values.
作者：
Aaij, R.;Beteta, C. Abellan;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
EUROPEAN PHYSICAL JOURNAL C,2020年80(3):1-23 ISSN：1434-6044
通讯作者：
Saur, M.;Li, P. -R.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; de Vries, J. A.; Kopecna, R.; Veronesi, M.; Aaij, R.; Greim, R.; van Beuzekom, M.; 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 Subatom Phys, Amsterdam, Netherlands.;[Tourinho Jadallah Aoude, R.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Soares Lavra, L.; Kucewicz, W.; Gomes, A.; Bediaga, I.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Rangel, M. S.; Otalora Goicochea, J. M.; Carvalho Akiba, K.; Rodrigues, F. Ferreira; Silva de Oliveira, L.; De Paula, L.; Nasteva, I.; Da Cunha Marinho, F.; Amato, S.] Univ Fed Rio 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.; Zhang, L.; 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：
[Saur, M.] U;[Li, P. -R.] L;Univ Chinese Acad Sci, Beijing, Peoples R China.;Lanzhou Univ, Lanzhou, Peoples R China.
摘要：
The cross-sections of $$\psi {(2S)}$$ meson production in proton-proton collisions at $$\sqrt{s} =13\text { TeV} $$ are measured with a data sample collected by the LHCb detector corresponding to an integrated luminosity of $$275\text { pb} ^{-1} $$. The production cross-sections for prompt $$\psi {(2S)}$$ mesons and those for $$\psi {(2S)}$$ mesons from b-hadron decays ($${\psi {(2S)}} \text{-from- }{b} $$) are determined as functions of the transverse momentum, $$p_{\mathrm {T}}$$, and the rapidity, y, of the $$\psi {(2S)}$$ meson in the kinematic range $$2<p_{\mathrm {T}} <20\text { GeV/}c $$ and $$2.0<y<4.5$$. The production cross-sections integrated over this kinematic region are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},13\text { TeV})\\&\quad =1.430\pm 0.005\text { (stat)} \pm 0.099\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},13\text { TeV})\\&\quad =0.426\pm 0.002\text { (stat)} \pm 0.030\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$A new measurement of $$\psi {(2S)}$$ production cross-sections in pp collisions at $$\sqrt{s}=7\text { TeV} $$ is also performed using data collected in 2011, corresponding to an integrated luminosity of $$614\text { pb} ^{-1} $$. The integrated production cross-sections in the kinematic range $$3.5<p_{\mathrm {T}} <14\text { GeV/}c $$ and $$2.0<y<4.5$$ are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},7\text { TeV})\\&\quad =0.471\pm 0.001\text { (stat)} \pm 0.025\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},7\text { TeV})\\&\quad =0.126\pm 0.001\text { (stat)} \pm 0.008\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$All results show reasonable agreement with theoretical calculations.
作者：
Aaij, R.*;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
PHYSICAL REVIEW D,2020年102(9) ISSN：2470-0010
通讯作者：
Aaij, R.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Usachov, A.; Hart, R.; Kuindersma, H. S.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Bediaga, I; Baptista Leite, J.] Ctr Brasileiro Pesquisas Fis 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.; Ferreira Rodrigues, F.; Nasteva, I; Garcia, L. Meyer; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Jiang, F.; Fan, J.; Ren, Z.; Xu, L.; Tang, Z.; Wang, M.; Zhang, W. C.; Gu, C.; 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.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
摘要：
A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations.
作者：
Aaij, R.;Beteta, C. Abellan;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
Journal of High Energy Physics,2020年2020(6):1-30 ISSN：1029-8479
通讯作者：
Vieites Diaz, M.
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.
关键词：
B physics;Flavor physics;Hadron-Hadron scattering (experiments);Heavy quark production;Polarization
摘要：
This paper presents an analysis of the
$$ {\Lambda}_b^0 $$
→ J/ψΛ angular distribution and the transverse production polarisation of
$$ {\Lambda}_b^0 $$
baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb−1, collected with the LHCb experiment. The polarisation is determined in a fiducial region of
$$ {\Lambda}_b^0 $$
transverse momentum and pseudorapidity of 1 < pT < 20 GeV/c and 2 < η < 5, respectively. The data are consistent with
$$ {\Lambda}_b^0 $$
baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Λ → pπ− decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration.
作者：
Aaij, R.;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
Journal of High Energy Physics,2020年2020(3):1-22 ISSN：1029-8479
通讯作者：
Smith, M.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; Hart, R.; Kuindersma, H. S.; de Vries, J. A.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Bel, L. J.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Onderwater, C. J. G.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Soares Lavra, L.; Gomes, A.; dos Reis, A. C.; Bediaga, I] Ctr Brasileiro Pesquisas Fis, 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.; Silva de Oliveira, L.; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Yang, Z.; Cai, H.; Zhang, S.; Jiang, F.; Fan, J.; Xu, A.; Liu, G.; Ren, Z.; Xu, L.; Tang, Z.; Li, H.; Hicheur, A.; Wang, J.; Sellam, S.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Xing, H.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Gao, Y.] Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China.
关键词：
B physics;Branching fraction;Flavor physics;Hadron-Hadron scattering (experiments)
摘要：
The Cabibbo-suppressed semileptonic decay
$$ {B}^{+}\to p\overline{p}{\mu}^{+}{\nu}_{\mu } $$
is observed for the first time using a sample of pp collisions corresponding to an integrated luminosity of 1.0, 2.0 and 1.7 fb−1 at centre-of-mass energies of 7, 8 and 13 TeV, respectively. The differential branching fraction is measured as a function of the
$$ p\overline{p} $$
invariant mass using the decay mode B+ → J/ψK+ for normalisation. The total branching fraction is measured to be
$$ \mathrm{\mathcal{B}}\left({B}^{+}\to p\overline{p}{\mu}^{+}{\nu}_{\mu}\right)=\left({5.27}_{-0.24}^{+0.23}\pm 0.21\pm 0.15\right)\times {10}^{-6}, $$
where the first uncertainty is statistical, the second systematic and the third is from the uncertainty on the branching fraction of the normalisation channel.
作者：
Aaij, R.*;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
PHYSICAL REVIEW D,2020年102(7) ISSN：2470-0010
通讯作者：
Aaij, R.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Mauri, A.; Usachov, A.; Hart, R.; Lukashenko, V; Kuindersma, H. S.; de Vries, J. A.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; De Bruyn, K.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Greeven, L. M.; Esen, S.; Geertsema, R. E.; Pellegrino, A.; Vitkovskiy, A.; Gabriel, E.; Merk, M.; Onderwater, C. J. G.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Pawley, C. J.; Akiba, K. Carvalho; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Gomes, A.; Torres Machado, D.; dos Reis, A. C.; Bediaga, I; Baptista Leite, J.] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Gobel, C.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Nasteva, I; Sellam, S.; Otalora Goicochea, J. M.; De Paula, L.; Amato, S.; Meyer Garcia, L.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Cai, H.; Jiang, F.; Bian, L.; Dey, B.; Fan, J.; Liu, G.; Ren, Z.; Xu, L.; Tang, Z.; Denis, X.; Li, H.; Wang, J.; Wang, M.; Hu, J.; Gu, C.; Xing, H.; Kang, Y.; Fang, B.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Gao, Y.; Zhang, S.; Xu, A.; Wang, J.; Xu, Z.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
摘要：
The Xi(0)(c) baryon is unstable and usually decays into charmless final states by the c -> sud transition. It can, however, also disintegrate into a pi(-) meson and a Lambda(+)(c) baryon via s quark decay or via cs -> dc weak scattering. The interplay between the latter two processes governs the size of the branching fraction B(Xi(0)(c) -> pi(-) Lambda(+)(c)), first measured here to be (0.55 +/- 0.02 +/- 0.18)%, where the first uncertainty is statistical and second systematic. This result is compatible with the larger of the theoretical predictions that connect models of hyperon decays using partially conserved axial currents and SU(3) symmetry with those involving the heavy-quark expansion and heavy-quark symmetry. In addition, the branching fraction of the normalization channel, B(Xi(+)(c) -> pK(-) pi(+)) = (1.135 +/- 0.002 +/- 0.387)% is measured.
作者：
Aaij, R.;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
Journal of High Energy Physics,2020年2020(6):1-25 ISSN：1029-8479
通讯作者：
Hill, D.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Usachov, A.; Hart, R.; Kuindersma, H. S.; de Vries, J. A.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Bel, L. J.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Sierra, C. V. Azquez; Merk, M.; Onderwater, C. J. G.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Govorkova, E.; Schubiger, M.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Gomes, A.; Torres Machado, D.; dos Reis, A. C.; Bediaga, I] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Gobel, C.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Nasteva, I; Sellam, S.; Otalora Goicochea, J. M.; Silva de Oliveira, L.; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Cai, H.; Jiang, F.; Fan, J.; Liu, G.; Ren, Z.; Xu, L.; Tang, Z.; Li, H.; Wang, J.; Wang, M.; Zhang, W. C.; Gu, C.; Xing, H.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China.
关键词：
B physics;CKM angle gamma;CP violation;Flavor physics;Hadron-Hadron scattering (experiments)
摘要：
Measurements of CP observables in B-+/- -> DK +/- and B-+/- -> D pi (+/-) decays are presented, where D represents a superposition of D-0 and D<overbar></mml:mover>0 states. The D meson is reconstructed in the three-body final states KS0K +/- pi -/+ and KS0K -/+ pi <mml:mo>+/-. The analysis uses samples of B mesons produced in proton-proton collisions, corresponding to an integrated luminosity of 1.0, 2.0, and 6.0 fb(-1) collected with the LHCb detector at centre-of-mass energies of <mml:msqrt>s</mml:msqrt> = 7, 8, and 13 TeV, respectively. These measurements are the most precise to date, and provide important input for the determination of the CKM angle gamma.<fig id="Figa" position="anchor"><graphic position="anchor" specific-use="HTML" mime-subtype="JPEG" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13130_2020_13157_Figa_HTML.jpg" id="MO1"></graphic
作者：
Aaij, R.;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinol, M.;...
期刊：
Journal of High Energy Physics,2020年2020(5):1-27 ISSN：1029-8479
通讯作者：
Lisovskyi, V
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Hart, R.; Heijho, K.; Kuindersma, H. S.; de Vries, J. A.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Bel, L. J.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Onderwater, C. J. G.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Cruz Torres, M.; De Miranda, J. M.; Soares Lavra, L.; Gomes, A.; Torres Machado, D.; Erri, A. Massa; dos Reis, A. C.; Bediaga, I] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Gandelman, M.; Gobel, C.; Rangel, M. S.; Hicheur, A.; Nasteva, I; Sellam, S.; Otalora Goicochea, J. M.; Rodrigues, F. Ferreira; Silva de Oliveira, L.; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Cai, H.; Jiang, F.; Fan, J.; Liu, G.; Ren, Z.; Xu, L.; Tang, Z.; Li, H.; Wang, J.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Xing, H.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China.
摘要：
The ratio of branching fractions of the decays
$$ {\Lambda}_b^0 $$
→ pK−e+e− and
$$ {\Lambda}_b^0 $$
→ pK−μ+μ−,
$$ {R}_{pK}^{-1} $$
, is measured for the first time using proton-proton collision data corresponding to an integrated luminosity of 4.7 fb−1 recorded with the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV. In the dilepton mass-squared range 0.1 < q2 < 6.0 GeV2/c4 and the pK− mass range m(pK−) < 2600 MeV/c2, the ratio of branching fractions is measured to be
$$ {R}_{pK}^{-1}={1.17}_{-0.16}^{+0.18}\pm 0.07 $$
, where the first uncertainty is statistical and the second systematic. This is the first test of lepton universality with b baryons and the first observation of the decay
$$ {\Lambda}_b^0 $$
→ pK−e+e−.
作者：
Aaij, R.*;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
PHYSICAL REVIEW D,2020年102(5) ISSN：2470-0010
通讯作者：
Aaij, R.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Hynds, D.; van Tilburg, J.; Hart, R.; Kuindersma, H. S.; de Vries, J. A.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Bel, L. J.; Esen, S.; Dall'Occo, E.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Onderwater, C. J. G.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; 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; dos Reis, A. C.; Bediaga, I] Ctr Brasileiro Pesquisas Fis 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.; Ferreira Rodrigues, F.; Hicheur, A.; Nasteva, I; Sellam, S.; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Cai, H.; Zhang, S.; Jiang, F.; Fan, J.; Xu, A.; Liu, G.; Ren, Z.; Xu, L.; Tang, Z.; Li, H.; Wang, J.; Xu, Z.; Wang, M.; Zhang, W. C.; Gu, C.; Sun, J.; Xing, H.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Mu, H.; Zeng, M.; Zhang, L.; Gan, Y.; Liu, X.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Gao, Y.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
摘要：
A search for CP violation in the Lambda(0)(b) -> p pi(-) pi(+) pi(-) decay is performed using LHCb data corresponding to an integrated luminosity of 6.6 fb(-1) collected in pp collisions at center-of-mass energies of 7, 8 and 13 TeV. The analysis uses both triple product asymmetries and the unbinned energy test method. The highest significances of CP asymmetry are 2.9 standard deviations from triple product asymmetries and 3.0 standard deviations for the energy test method. Once the global p-value is considered, all results are consistent with no CP violation. Parity violation is observed at a significance of 5.5 standard deviations for the triple product asymmetry method and 5.3 standard deviations for the energy test method. The reported deviations are given in regions of phase space.
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：
We report four narrow peaks in the Xi K-0(b)- mass spectrum obtained using pp collisions at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb(-1) recorded by the LHCb experiment. Referring to these states by their mass, the mass values are m[Omega(b)(6316)(-)] = 6315.64 +/- 0.31 +/- 0.07 +/- 0.50 MeV, m[Omega(b)(6330)(-)] = 6330.30 +/- 0.28 +/- 0.07 +/- 0.50 MeV, m[Omega(b)(6340)(-)] = 6339.71 +/- 0.26 +/- 0.05 +/- 0.50 MeV, m[Omega(b)(6350)(-)] = 6349.88 +/- 0.35 +/- 0.05 +/- 0.50 MeV, where the uncertainties are statistical, systematic, and the last is due to the knowledge of the Xi(0)(b) mass. The natural widths of the three lower mass states are consistent with zero, and the 90% confidence-level upper limits are determined to be Gamma[Omega(b)(6316)(-)] < 2.8 MeV, Gamma[Omega(b)(6330)(-)] < 3.1 MeV and Gamma[Omega(b)(6340)-] < 1.5 MeV. The natural width of the Omega(b)(6350)(-) peak is 1.4(-0.8)(+1.0) +/- 0.1 MeV, which is 2.5 sigma from zero and corresponds to an upper limit of 2.8 MeV. The peaks have local significances ranging from 3.6 sigma to 7.2 sigma. After accounting for the look-elsewhere effect, the significances of the Omega(b)(6316)(-) and Omega(b)(6330)(-) peaks are reduced to 2.1 sigma and 2.6 sigma, respectively, while the two higher mass peaks exceed 5 sigma. The observed peaks are consistent with expectations for excited Omega(-)(b) resonances.
作者：
Aaij, R.*;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
Journal of High Energy Physics,2020年2020(7):1-21 ISSN：1029-8479
通讯作者：
Aaij, R.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Usachov, A.; Hart, R.; Kuindersma, H. S.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Benson, S.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Bediaga, I; Baptista Leite, J.] Ctr Brasileiro Pesquisas Fis 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.; Ferreira Rodrigues, F.; Nasteva, I; Garcia, L. Meyer; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Jiang, F.; Fan, J.; Ren, Z.; Xu, L.; Tang, Z.; Wang, M.; Zhang, W. C.; Gu, C.; 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.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
关键词：
B physics;Hadron-Hadron scattering (experiments);QCD;Spectroscopy
摘要：
A precision measurement of the
$$ {B}_c^{+} $$
meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 9.0 fb−1. The
$$ {B}_c^{+} $$
mesons are reconstructed via the decays
$$ {B}_c^{+} $$
→ J/ψπ+,
$$ {B}_c^{+} $$
→ J/ψπ+π−π+,
$$ {B}_c^{+}\to J/\psi p\overline{p}{\pi}^{+} $$
,
$$ {B}_c^{+}\to J/\psi {D}_s^{+} $$
,
$$ {B}_c^{+} $$
→ J/ψ D0K+ and
$$ {B}_c^{+}\to {B}_s^0{\pi}^{+} $$
. Combining the results of the individual decay channels, the
$$ {B}_c^{+} $$
mass is measured to be 6274.47 ± 0.27 (stat) ± 0.17 (syst) MeV/c2. This is the most precise measurement of the
$$ {B}_c^{+} $$
mass to date. The difference between the
$$ {B}_c^{+} $$
and
$$ {B}_s^0 $$
meson masses is measured to be 907.75 ± 0.37 (stat) ± 0.27 (syst) MeV/c.
作者：
Aaij, R.*;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
Journal of High Energy Physics,2020年2020(8):1-29 ISSN：1029-8479
通讯作者：
Aaij, R.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Usachov, A.; Hart, R.; Kuindersma, H. S.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Bediaga, I; Baptista Leite, J.] Ctr Brasileiro Pesquisas Fis 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.; Ferreira Rodrigues, F.; Nasteva, I; Garcia, L. Meyer; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Jiang, F.; Fan, J.; Ren, Z.; Xu, L.; Tang, Z.; Wang, M.; Zhang, W. C.; Gu, C.; 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.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
关键词：
B physics;Branching fraction;Hadron-Hadron scattering (experiments);Quarkonium;Spectroscopy
摘要：
The decays B+ → J/ψπ+π−K+ are studied using a data set corresponding to an integrated luminosity of 9 fb−1 collected with the LHCb detector in proton-proton collisions between 2011 and 2018. Precise measurements of the ratios of branching fractions with the intermediate ψ2(3823), χc1(3872) and ψ(2S) states are reported. The values are
$$ {\displaystyle \begin{array}{c}\frac{{\mathcal{B}}_{{\mathrm{B}}^{+}\to {\uppsi}_2(3823){\mathrm{K}}^{+}}\times {\mathcal{B}}_{\uppsi_2(3823)\to \mathrm{J}/{\uppsi \uppi}^{+}{\uppi}^{-}}}{{\mathcal{B}}_{{\mathrm{B}}^{+}\to {\upchi}_{\mathrm{c}1}(3872){\mathrm{K}}^{+}}\times {\mathcal{B}}_{\upchi_{\mathrm{c}1}(3872)\to \mathrm{J}/{\uppsi \uppi}^{+}{\uppi}^{-}}}=\left(3.56\pm 0.67\pm 0.11\right)\times {10}^{-2},\\ {}\frac{{\mathcal{B}}_{{\mathrm{B}}^{+}\to {\uppsi}_2(3823){\mathrm{K}}^{+}}\times {\mathcal{B}}_{\uppsi_2(3823)\to \mathrm{J}/{\uppsi \uppi}^{+}{\uppi}^{-}}}{{\mathcal{B}}_{{\mathrm{B}}^{+}\to \uppsi \left(2\mathrm{S}\right){\mathrm{K}}^{+}}\times {\mathcal{B}}_{\uppsi \left(2\mathrm{S}\right)\to \mathrm{J}/{\uppsi \uppi}^{+}{\uppi}^{-}}}=\left(1.31\pm 0.25\pm 0.04\right)\times {10}^{-3},\\ {}\frac{{\mathcal{B}}_{\mathrm{B}+\to {\upchi}_{\mathrm{c}1}(3872){\mathrm{K}}^{+}}\times {\mathcal{B}}_{\upchi_{\mathrm{c}1}(3872)\to \mathrm{J}/{\uppsi \uppi}^{+}{\uppi}^{-}}}{{\mathcal{B}}_{{\mathrm{B}}^{+}\to \uppsi \left(2\mathrm{S}\right){\mathrm{K}}^{+}}\times {\mathcal{B}}_{\uppsi \left(2\mathrm{S}\right)\to \mathrm{J}/{\uppsi \uppi}^{+}{\uppi}^{-}}}=\left(3.69\pm 0.07\pm 0.06\right)\times {10}^{-2},\end{array}} $$
where the first uncertainty is statistical and the second is systematic. The decay of B+ → ψ2(3823)K+ with ψ2(3823) → J/ψπ+π− is observed for the first time with a significance of 5.1 standard deviations. The mass differences between the ψ2(3823), χc1(3872) and ψ(2S) states are measured to be
$$ {\displaystyle \begin{array}{c}{m}_{\upchi_{\mathrm{c}1}(3872)}-{m}_{\uppsi_2(3823)}=47.50\pm 0.53\pm 0.13\;\mathrm{MeV}/{c}^2,\\ {}{m}_{\uppsi_2(3823)}-{m}_{\uppsi_2\left(2\mathrm{S}\right)}=137.98\pm 0.53\pm 0.14\;\mathrm{MeV}/{c}^2,\\ {}{m}_{\upchi_{\mathrm{c}1}(3872)}-{m}_{\uppsi_2\left(2\mathrm{S}\right)}=185.49\pm 0.06\pm 0.03\;\mathrm{MeV}/{c}^2,\end{array}} $$
resulting in the most precise determination of the χc1(3872) mass. The width of the ψ2(3823) state is found to be below 5.2 MeV at 90% confidence level. The Breit-Wigner width of the χc1(3872) state is measured to be
$$ {\Gamma}_{\upchi_{\mathrm{c}1}(3872)}^{\mathrm{BW}}={0.96}_{-0.18}^{+0.19}\pm 0.21\;\mathrm{MeV} $$
which is inconsistent with zero by 5.5 standard deviations.
作者：
Aaij, R.;Beteta, C. Abellan;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
Journal of High Energy Physics,2020年(12) ISSN：1029-8479
通讯作者：
Vieites Diaz, M.
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：
An angular analysis of the B-0 -> K*(0)e(+)e(-) decay is performed using a data sample corresponding to an integrated luminosity of 9 fb(-1) of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared (q(2)) interval between 0.0008 and 0.257 GeV2, where the rate is dominated by the B-0 -> K*(0)gamma transition with a virtual photon. The fraction of longitudinal polarisation of the K*(0) meson, F-L, is measured to be F-L = (4.4 +/- 2.6 +/- 1.4)%, where the first uncertainty is statistical and the second systematic. The A(T)(Re) observable, which is related to the lepton forward-backward asymmetry, is measured to be A(T)(Re) = -0.06 +/- 0.08 +/- 0.02. The A(T)((2)) and A(T)(Im) transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be A(T)((2)) = 0.11 +/- 0.10 +/- 0.02 and A(T)(Im) = 0.02 +/- 0.10 +/- 0.01. The results are consistent with Standard Model predictions and provide the world's best constraint on the b -> s gamma photon polarisation.
摘要：
A novel compact Vivaldi Antenna (CVA) for short-pulse ground penetrating radar (GPR) systems is presented. Artificial materials lens (AML) and sidelobe suppressor (SSR) are loaded to improve GPR Antenna & x2019;s radiation capability in the aperture and the flanks of the CVA. The simulation and experimental results indicate that the proposed CVA has a & x2212;10 dB impedance bandwidth of 100 & x0025; (0.7-2.1 GHz) and a & x2212;3 dB gain bandwidth of 70.9 & x0025; (1.0-2.1 GHz). Within the operating bandwidth of the CVA, AML primarily enhances the CVA & x2019;s high-frequency gain (1.4-2.1GHz), while the SSR primarily enhances the CVA & x2019;s low-frequency gain (0.7-1.4 GHz). Moreover, the CVA loaded with two kinds of artificial materials (AMs) has an average gain of 1 dB and 2 dB in the low-frequency and high-frequency parts, respectively. In addition, the transmission response with small ringing in time domain makes the proposed CVA suitable for short-pulse GPR systems. AML and SSR effectively enhance the gain of the CVA with a compact and space-saving loading method, which provides a new idea to enhance the gain of the CVA by artificial material.
作者：
Aaij, R.;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
Journal of High Energy Physics,2020年2020(11) ISSN：1029-8479
通讯作者：
Xiang, Z.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Usachov, A.; Hart, R.; Kuindersma, H. S.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Bediaga, I; Baptista Leite, J.] Ctr Brasileiro Pesquisas Fis 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.; Ferreira Rodrigues, F.; Nasteva, I; Garcia, L. Meyer; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Jiang, F.; Fan, J.; Ren, Z.; Xu, L.; Tang, Z.; Wang, M.; Zhang, W. C.; Gu, C.; 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.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
通讯机构：
[Xiang, Z.] U;Univ Chinese Acad Sci, Beijing, Peoples R China.
关键词：
B physics;Hadron-Hadron scattering (experiments);Heavy quark production;QCD;Spectroscopy
作者：
Aaij, R.;Beteta, C. Abellan;Adeva, B.;Adinolfi, M.;Aidala, C. A.;...
期刊：
PHYSICAL REVIEW D,2020年101(1) ISSN：2470-0010
通讯作者：
Vieites Diaz, M.
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.
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.
关键词：
charmed baryons;limits on production of particles;charmed quarks;experimental tests
摘要：
A search for the doubly charmed baryon $$\Xi_{cc}^+$$ is performed through its decay to the $$\Lambda_c^ + {K^ -}{\pi ^ +}$$ final state, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data correspond to a total integrated luminosity of 9 fb−1. No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c2. Upper limits are set at 95% credibility level on the ratio of the $$\Xi_{cc}^+$$ production cross-section times the branching fraction to that of $$\Lambda_c^ + $$ and $$\Xi_{cc}^{+ +}$$ baryons. The limits are determined as functions of the $$\Xi_{cc}^+$$ mass for different lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.
通讯机构：
[Yu, Ying] C;Cent China Normal Univ, Coll Phys Sci & Technol, Inst Nanosci & Nanotechnol, Wuhan 430079, Peoples R China.
关键词：
CO2 reduction;Cu2[email protected];Heterostructured nanorods;In situ fabrication;Visible-light
摘要：
Cuprous oxide (Cu2O) is known to be a promising photocatalyst for CO2 reduction into solar fuels under visible-light irradiation. However, the issues of fast recombination of photogenerated carriers and photocorrosion severely limit its photocatalytic (PC) performance. Herein, we report a unique design of one-dimensional (1D) Cu2O@Cu metal-semiconductor heterostructured nanorods via a simple in situ reduction method for efficient CO2 reduction to hydrocarbons fuels. The well-defined 1D Cu2O nanorod arrays ensure excellent visible-light harvesting capability, and the in situ fabricated Cu2O@Cu heterostructure endows the catalyst with enhanced conductivity as well as highly improved separation and transfer efficiency of photogenerated carriers. Consequently, the optimized Cu2O@Cu heterostructure achieves an apparent quantum efficiency of 2.40% for CH4 and C2H4 and as high as 92% activity retained after four PC cycles. Furthermore, the CO2 reduction performance was further improved when applied a low external bias. This study not only provides a novel, low-cost, and efficient strategy to address the stability and activity issues of Cu2O, but also sheds light on the development of active and robust photocatalysts for energy conversion and storage.
作者：
Aaij, R.*;Beteta, C. Abellan;Ackernley, T.;Adeva, B.;Adinolfi, M.;...
期刊：
PHYSICAL REVIEW D,2020年102(11) ISSN：2470-0010
通讯作者：
Aaij, R.
作者机构：
[Ketel, T.; Tuning, N.; Hynds, D.; Perez, D. H. Campora; Usachov, A.; Hart, R.; Kuindersma, H. S.; Heijhoff, K.; Veronesi, M.; Aaij, R.; Snoch, A.; Greim, R.; van Beuzekom, M.; Martinez, M. Lucio; Kostiuk, I; Jans, E.; Esen, S.; Pellegrino, A.; Vitkovskiy, A.; Merk, M.; Butter, J. S.; Koppenburg, P.; Akiba, K. Carvalho; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Sierra, C. Vazquez; Govorkova, E.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Bediaga, I; Baptista Leite, J.] Ctr Brasileiro Pesquisas Fis 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.; Ferreira Rodrigues, F.; Nasteva, I; Garcia, L. Meyer; De Paula, L.; Amato, S.] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil.;[Yang, Z.; Jiang, F.; Fan, J.; Ren, Z.; Xu, L.; Tang, Z.; Wang, M.; Zhang, W. C.; Gu, C.; 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.;[Gao, Y.; Zhang, S.; Xu, A.; Xu, Z.] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing, Peoples R China.
摘要：
The relative branching fractions of B+ -> h(+)h('+)h('-) decays, where h((')) is a pion or kaon, are measured. The analysis is performed with a data sample, collected with the LHCb detector, corresponding to an integrated luminosity of 3.0 fb(-1) of pp collisions. The results obtained improve significantly on previous measurements of these quantities, and are important for the interpretation of Dalitz plot analyses of three-body charmless hadronic decays of B+ mesons.
