| Records |
| Author |
LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Search for long-lived particles decaying to e(+/-)mu(-/+)nu |
Type |
Journal Article |
| Year |
2021 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
81 |
Issue |
3 |
Pages |
261 - 16pp |
| Keywords |
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| Abstract |
Long-lived particles decaying to e(+/-) mu(-/+)nu, with masses between 7 and 50 GeV/c(2) and lifetimes between 2 and 50 ps, are searched for by looking at displaced vertices containing electrons and muons of opposite charges. The search is performed using 5.4 fb(-1) of pp collisions collected with the LHCb detector at a centre-of-mass energy of root s = 13 TeV. Three mechanisms of production of long-lived particles are considered: the direct pair production from quark interactions, the pair production from the decay of a Standard-Model-like Higgs boson with a mass of 125 GeV/c(2), and the charged current production from an on-shell W boson with an additional lepton. No evidence of these long-lived states is obtained and upper limits on the production cross-section times branching fraction are set on the different production modes. |
Address  |
[Amato, S.; De Paula, L.; Rodrigues, F. Ferreira; Gandelman, M.; Hicheur, A.; Lopes, J. H.; Garcia, L. Meyer; Nasteva, I; Goicochea, J. M. Otalora; Polycarpo, E.; Rangel, M. S.; De Almeida, F. L. Souza; De Paula, B. Souza] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil, Email: matthieu.marinangeli@gmail.com |
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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1434-6044 |
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Expedition |
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Conference |
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| Notes |
WOS:000634800600002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4771 |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Evidence for a New Structure in the J/psi p and J/psi(p)over-bar Systems in B-s(0) -> J/psi p(p)over-bar Decays |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
128 |
Issue |
6 |
Pages |
062001 - 11pp |
| Keywords |
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| Abstract |
An amplitude analysis of flavor-untagged B-s(0) -> J=psi p (p) over bar decays is performed using a sample of 797 +/- 31 decays reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity of 9 fb(-1). Evidence for a new structure in the J=psi p and J=psi(p) over bar systems with a mass of 4337(-4-2)(+7+2) MeV and a width of 29(-12-14)(+26+14) MeV is found, where the first uncertainty is statistical and the second systematic, with a significance in the range of 3.1 to 3.7 sigma, depending on the assigned J(P) hypothesis. |
| Address |
[Aaij, R.; Leite, J. Baptist; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; Dos Reis, A. C.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil |
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| Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0031-9007 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000759202300001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5157 |
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| Author |
LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Precise determination of the B-s(0)-B-s(-0) oscillation frequency |
Type |
Journal Article |
| Year |
2022 |
Publication |
Nature Physics |
Abbreviated Journal |
Nat. Phys. |
| Volume |
18 |
Issue |
|
Pages |
54-58 |
| Keywords |
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| Abstract |
Mesons comprising a beauty quark and strange quark can oscillate between particle (B-s(0)) and antiparticle (B-s(-0)) flavour eigenstates, with a frequency given by the mass difference between heavy and light mass eigenstates, Delta m(s). Here we present a measurement of Delta m(s) using B-s(0) -> D-s(-)pi(+) decays produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The oscillation frequency is found to be Delta m(s) = 17.7683 +/- 0.0051 +/- 0.0032 ps(-1), where the first uncertainty is statistical and the second is systematic. This measurement improves on the current Delta m(s) precision by a factor of two. We combine this result with previous LHCb measurements to determine Delta m(s) = 17.7656 +/- 0.0057 ps(-1), which is the legacy measurement of the original LHCb detector. |
| Address |
[Aaij, R.; Butter, J. S.; Akiba, K. Carvalho; Sole, S. Ferreres; Gabriel, E.; Geertsema, R. E.; Greeven, L. M.; Heijhoff, K.; Hulsbergen, W.; Hynds, D.; Jans, E.; Klaver, S.; Koppenburg, P.; Kostiuk, I; Kuindersma, H. S.; Martinez, M. Lucio; Lukashenko, V; Mauri, A.; Merk, M.; Pellegrino, A.; Sanchez Gras, C.; Schubiger, M.; Snoch, A.; Tuning, N.; Usachov, A.; van Beuzekom, M.; Veronesi, M.] Nikhef Natl Inst Subatom Phys, Amsterdam, Netherlands, Email: alessandro.bertolin@pd.infn.it |
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Thesis |
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| Publisher |
Nature Portfolio |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1745-2473 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000739810100002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5075 |
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| Author |
LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Test of lepton universality in beauty-quark decays |
Type |
Journal Article |
| Year |
2022 |
Publication |
Nature Physics |
Abbreviated Journal |
Nat. Phys. |
| Volume |
18 |
Issue |
3 |
Pages |
277-282 |
| Keywords |
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| Abstract |
The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN's Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons. |
| Address |
[Aaij, R.; Butter, J. S.; Akiba, K. Carvalho; Sole, S. Ferreres; Gabriel, E.; Geertsema, R. E.; Greeven, L. M.; Heijhoff, K.; Hulsbergen, W.; Hynds, D.; Jans, E.; Ketel, T.; Klaver, S.; Koppenburg, P.; Kostiuk, I; Kuindersma, H. S.; Martinez, M. Lucio; Lukashenko, V; Mauri, A.; Merk, M.; Pellegrino, A.; Raven, G.; Gras, C. Sanchez; Schubiger, M.; Soares, M. Senghi; Snoch, A.; Tuning, N.; Usachov, A.; Van Beuzekom, M.; Veronesi, M.] Nikhef Natl Inst Subatom Phys, Amsterdam, Netherlands, Email: alessandro.bertolin@pd.infn.it |
| Corporate Author |
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Thesis |
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| Publisher |
Nature Portfolio |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1745-2473 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000769534600020 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5166 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Observation of an exotic narrow doubly charmed tetraquark |
Type |
Journal Article |
| Year |
2022 |
Publication |
Nature Physics |
Abbreviated Journal |
Nat. Phys. |
| Volume |
18 |
Issue |
|
Pages |
751-754 |
| Keywords |
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| Abstract |
Conventional, hadronic matter consists of baryons and mesons made of three quarks and a quark-antiquark pair, respectively(1,2). Here, we report the observation of a hadronic state containing four quarks in the Large Hadron Collider beauty experiment. This so-called tetraquark contains two charm quarks, a (u) over bar and a (d) over tilde quark. This exotic state has a mass of approximately 3,875 MeV and manifests as a narrow peak in the mass spectrum of (DD0)-D-0 pi(+) mesons just below the D*D-+(0) mass threshold. The near-threshold mass together with the narrow width reveals the resonance nature of the state. |
| Address |
[Aaij, R.; Butter, J. S.; Akiba, K. Carvalho; Sole, S. Ferreres; Gabriel, E.; Geertsema, R. E.; Greeven, L. M.; Heijhoff, K.; Hulsbergen, W.; Hynds, D.; Jans, E.; Ketel, T.; Klaver, S.; Koppenburg, P.; Kostiuk, I; Kuindersma, H. S.; Martinez, M. Lucio; Lukashenko, V; Mauri, A.; Merk, M.; Pellegrino, A.; Raven, G.; Gras, C. Sanchez; Schubiger, M.; Soares, M. Senghi; Snoch, A.; Tuning, N.; Usachov, A.; Van Beuzekom, M.; Veronesi, M.] Nikhef Natl Inst Subatom Phys, Amsterdam, Netherlands |
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Thesis |
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| Publisher |
Nature Portfolio |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1745-2473 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000811954400004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5279 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Study of the doubly charmed tetraquark T-cc(+) |
Type |
Journal Article |
| Year |
2022 |
Publication |
Nature Communications |
Abbreviated Journal |
Nat. Commun. |
| Volume |
13 |
Issue |
1 |
Pages |
3351 - 19pp |
| Keywords |
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| Abstract |
Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the (DD0)-D-0 pi(+) mass spectrum just below the D*+D-0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T-cc(+), tetraquark with a quark content of cc (u) over bar(d) over bar and spin-parity quantum numbers J(P) =1(+). Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*(+) mesons is consistent with the observed D-0 pi(+) mass distribution. To analyse the mass of the resonance and its coupling to the DID system, a dedicated model is developed under the assumption of an isoscalar axial-vector T-cc(+), state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T-cc(+), state. In addition, an unexpected dependence of the production rate on track multiplicity is observed. |
| Address |
[Aaij, R.; Butter, J. S.; Akiba, K. Carvalho; Sole, S. Ferreres; Gabriel, E.; Geertsema, R. E.; Greeven, L. M.; Heijhoff, K.; Hulsbergen, W.; Hynds, D.; Jans, E.; Ketel, T.; Klaver, S.; Koppenburg, P.; Kostiuk, I; Kuindersma, H. S.; Martinez, M. Lucio; Lukashenko, V; Mauri, A.; Merk, M.; Pellegrino, A.; Raven, G.; Gras, C. Sanchez; Schubiger, M.; Soares, M. Senghi; Snoch, A.; Tuning, N.; Usachov, A.; van Beuzekom, M.; Veronesi, M.] Nikhef Natl Inst Subatom Phys, Amsterdam, Netherlands, Email: Ivan.Belyaev@cern.ch |
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Nature Portfolio |
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English |
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Expedition |
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Conference |
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| Notes |
WOS:000812556800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5280 |
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| Author |
LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Measurement of the prompt-production cross-section ratio sigma(chi(c2))/sigma(chi(c1)) in pPb collisions at root s(NN)=8.16 TeV |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
103 |
Issue |
6 |
Pages |
064905 - 10pp |
| Keywords |
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| Abstract |
This article reports the first measurement of prompt chi(c1) and chi(c2) charmonium production in nuclear collisions at Large Hadron Collider energies. The cross-section ratio sigma(chi(c2))/sigma(chi(c1)) is measured in pPb collisions at root s(NN) = 8.16 TeV, collected with the LHCb experiment. The chi(c1,2) states are reconstructed via their decay to a J/psi meson, subsequently decaying into a pair of oppositely charged muons, and a photon, which is reconstructed in the calorimeter or via its conversion in the detector material. The cross-section ratio is consistent with unity in the two considered rapidity regions. Comparison with a corresponding cross-section ratio previously measured by the LHCb Collaboration in pp collisions suggests that chi(c1) and chi(c2) states are similarly affected by nuclear effects occurring in pPb collisions. |
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Edition |
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2469-9985 |
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Expedition |
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Conference |
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| Notes |
WOS:000661749700003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4872 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jaimes Elles, S.J.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Rebollo De Miguel, M.; Remon Alepuz, C.; Ruiz Vidal, J.; Sanderswood, I. |
| Title |
A study of CP violation in the decays B± → [K+ K- π+π-]Dh± (h = K, π) and B± → [π+ π- π+ π-]Dh± |
Type |
Journal Article |
| Year |
2023 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
83 |
Issue |
6 |
Pages |
547 - 23pp |
| Keywords |
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| Abstract |
The first study of CP violation in the decay mode B-+/- -> [K+K-pi(+)pi(-)](D)h(+/-), with h = K, pi, is presented, exploiting a data sample of proton-proton collisions collected by the LHCb experiment that corresponds to an integrated luminosity of 9fb(-1). The analysis is performed in bins of phase space, which are optimised for sensitivity to local CP asymmetries. CP-violating observables that are sensitive to the angle gamma of the Unitarity Triangle are determined. The analysis requires external information on charm-decay parameters, which are currently taken from an amplitude analysis of LHCb data, but can be updated in the future when direct measurements become available. Measurements are also performed of phase-space integrated observables for B-+/- -> [K+K-pi(+)pi(-)](D)h(+/-) and B-+/- -> [pi(+)pi(-)pi(+)pi(-)](D)h(+/-) decays. |
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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1434-6044 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001117709800002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5945 |
| Permanent link to this record |
