arXiv subjects

F. J. Abudinen Gallego

Publications and source records attributed to F. J. Abudinen Gallego.

7 recordsLinked to original sources

arXiv2022

Study of the doubly charmed tetraquark $T_{cc}^+$

An exotic narrow state in the $D^0D^0π^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold is studied using a data set corresponding to an integrated luminosity of 9 fb$^{-1}$ acquired with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The state is consistent with the ground isoscalar $T^+_{cc}$ tetraquark with a quark content of $cc\bar{u}\bar{d}$ and spin-parity quantum numbers $\mathrm{J}^{\mathrm{P}}=1^+$. 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 confirmed by the $D^0π^+$ mass distribution. The mass of the resonance and its coupling to the $D^{*}D$ system are analysed. Resonance parameters including the pole position, scattering length, effective range and compositeness are measured 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.

hep-ex↗

arXiv2022

Observation of an exotic narrow doubly charmed tetraquark

Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. The observation of a new type of hadronic state, a doubly charmed tetraquark containing two charm quarks, an anti-$u$ and an anti-$d$ quark, is reported using data collected by the LHCb experiment at the Large Hadron Collider. This exotic state with a mass of about 3875 MeV$/c^2$ manifests itself as a narrow peak in the mass spectrum of $D^0D^0π^+$ mesons just below the $D^{*+}D^0$ mass threshold. The near threshold mass together with a strikingly narrow width reveals the resonance nature of the state.

hep-ex↗

arXiv2022

Study of $Z$ bosons produced in association with charm in the forward region

Events containing a $Z$ boson and a charm jet are studied for the first time in the forward region of proton-proton collisions. The data sample used corresponds to an integrated luminosity of $6 \, {\rm fb}^{-1}$ collected at a center-of-mass energy of 13 TeV with the LHCb detector. In events with a $Z$ boson and a jet, the fraction of charm jets is determined in intervals of $Z$-boson rapidity in the range $2.0 < y(Z) < 4.5$. A sizable enhancement is observed in the forward-most $y(Z)$ interval, which could be indicative of a valence-like intrinsic-charm component in the proton wave function.

hep-ex↗

arXiv2022

Identification of charm jets at LHCb

The identification of charm jets is achieved at LHCb for data collected in 2015-2018 using a method based on the properties of displaced vertices reconstructed and matched with jets. The performance of this method is determined using a dijet calibration dataset recorded by the LHCb detector and selected such that the jets are unbiased in quantities used in the tagging algorithm. The charm-tagging efficiency is reported as a function of the transverse momentum of the jet. The measured efficiencies are compared to those obtained from simulation and found to be in good agreement.

hep-ex↗

arXiv2022

Measurement of $χ_{c1}(3872)$ production in proton-proton collisions at $\sqrt{s}=8$ and $13$ TeV

The production cross-section of the $χ_{c1}(3872)$ state relative to the $ψ(2S)$ meson is measured using proton-proton collision data collected with the LHCb experiment at centre-of-mass energies of $\sqrt{s}=8$ and 13 TeV, corresponding to integrated luminosities of 2.0 and 5.4 fb$^{-1}$, respectively. The two mesons are reconstructed in the $J/ψπ^{+}π^{-}$ final state. The ratios of the prompt and nonprompt $χ_{c1}(3872)$ to $ψ(2S)$ production cross-sections are measured as a function of transverse momentum, $p_{\rm T}$, and rapidity, $y$, in the kinematic range $4 < p_{\rm T} < 20$ GeV/$c$ and $2.0 < y < 4.5$. The prompt ratio is found to increase with $p_{\rm T}$ independently of $y$. The double-differential cross-section ratio of $χ_{c1}(3872)$ relative to $ψ(2S)$ mesons between 13 and 8 TeV is also measured for the prompt component and observed to be consistent with unity, independent of $p_{\rm T}$ and centre-of-mass energy.

hep-ex↗

arXiv2022

Observation of the suppressed $Λ_b^0\to D p K^-$ decay with $D\to K^+ π^-$ and measurement of its $C\!P$ asymmetry

A study of $Λ_b^0$ baryon decays to the $DpK^-$ final state is presented based on a proton-proton collision data sample corresponding to an integrated luminosity of 9 fb$^{-1}$ collected with the LHCb detector. Two $Λ_b^0$ decays are considered, $Λ_b^0\to DpK^-$ with $D\to K^-π^+$ and $D\to K^+π^-$, where $D$ represents a superposition of $D^0$ and $\overline{D}^0$ states. The latter process is expected to be suppressed relative to the former, and is observed for the first time. The ratio of branching fractions of the two decays is measured, and the $C\!P$ asymmetry of the suppressed mode, which is sensitive to the CKM angle $γ$, is also reported.

hep-ex↗

arXiv2021

Study of the $B_c^+$ decays into charmonia and three light hadrons

Using proton-proton collision data, corresponding to an integrated luminosity of $9fb^{-1}$ collected with the LHCb detector, seven decay modes of the $B_c^+$ meson into a $J/ψ$ or $ψ(2S)$ meson and three charged hadrons, kaons or pions, are studied. The decays $B_c^+\rightarrow ( ψ(2S) \rightarrow J/ψπ^+ π^-)π^+ $, $B_c^+\rightarrow ψ(2S)π^+π^+π^-$, $B_c^+\rightarrow J/ψK^+π^+π^-$ and $B_c^+\rightarrow K^+K^+K^-$ are observed for the first time, and evidence for the $B_c^+\rightarrow ψ(2S)K^+K^-π^+$ decay is found, where $J/ψ$ and $ψ(2S)$ mesons are reconstructed in their dimuon decay modes. The ratios of branching fractions between the different $B_c^+$ decays are reported as well as the fractions of the decays proceeding via intermediate resonances. The results largely support the factorisation approach used for a theoretical description of the studied decays.

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