Publications de Christoph Frei

Angular analysis of B0->D-Ds+ with Ds+-> Ds+gamma decays

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini

The first full angular analysis of the B0 -> D-Ds+ decay is performed using 6 fb(-1) of pp collision data collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The Ds+-> Ds+gamma and D*- -> D0- vector meson decays ar ...

Springer Nature2021

Measurement of the CKM angle gamma and Bs0-Bs0 mixing frequency with Bs0 -> Ds -/+h +/-pi +/-pi-/+ decays

Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Luca Pescatore, Chitsanu Khurewathanakul

The CKM angle gamma is measured for the first time from mixing-induced CP violation between Bs0 -> Ds -/+ K pi +/- pi -/+ and Bs0 -> Ds +/- K -/+ pi -/+ pi +/- decays reconstructed in proton-proton collision data corresponding to an in ...

Springer Nature2021

Search for long-lived particles decaying to e(+/-)mu(-/+)nu

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini

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 ...

SPRINGER2021

Observation of New Resonances Decaying to J=Psi K plus and J=Psi phi

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini

The first observation of exotic states with a new quark content ccus decaying to the J/Psi K+ final state is reported with high significance from an amplitude analysis of the B+-> J/ Psi phi K+ decay. The analysis is carried out using proton-proton collisi ...

2021

Branching Fraction Measurements of the Rare B-s(0) -> phi mu(+)mu(-) and B-s(0)-> f(2)' (1525)mu(+)mu(-) Decays

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini

The branching fraction of the rare B-s(0) -> phi mu(+)mu(-) decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6 fb(-1), respectively. The bran ...

2021

Search for heavy neutral leptons in W plus . mu plus mu +/- jet decays

Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Luca Pescatore, Chitsanu Khurewathanakul

A search is performed for heavy neutrinos in the decay of a W boson into two muons and a jet. The data set corresponds to an integrated luminosity of approximately 3.0 fb-1 of proton-proton collision data at centre-of-mass energies of 7 and 8 TeV collected ...

SPRINGER2021

Evidence of a J/psi Lambda structure and observation of excited Xi(-) states in the Xi(-)(b) -> J/psi Lambda K- decay

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Tatsuya Nakada, Christoph Frei, Michel De Cian, Elena Graverini

First evidence of a structure in the J/psi Lambda invariant mass distribution is obtained from an amplitude analysis of Xi(-)(b) -> J/psi Lambda K- decays. The observed structure is consistent with being due to a charmonium pentaquark with strangeness with ...

2021

Measurement of the prompt-production cross-section ratio sigma(chi(c2))/sigma(chi(c1)) in pPb collisions at root s(NN)=8.16 TeV

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini

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 ...

2021

Observation of CP violation in two-body B-(s)(0)-meson decays to charged pions and kaons

Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Luca Pescatore, Chitsanu Khurewathanakul

The time-dependent CP asymmetries of B-0 -> pi(+)pi(-) and B-s(0) -> K+K- decays are measured using a data sample of pp collisions corresponding to an integrated luminosity of 1.9 fb(-1), collected with the LHCb detector at a centre-of-mass energy of 13TeV ...

Springer Nature2021

Search for CP violation in Xi(-)(b) -> pK(-)K(-) decays

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini

A search for CP violation in charmless three-body Xi(-)(b) -> pK(-)K(-) decays is performed using pp collision data recorded with the LHCb detector, corresponding to integrated luminosities of 1 fb(-1) at a center-of-mass energy root S = 7 TeV, 2 fb(-1) at ...

American Physical Society2021