LHCb is one of the four experiments at the Large Hadron Collider (CERN), dedicated to the study of b-hadrons. Throughout my research, I studied in particular b-baryons which are abundantly produced at the LHCb. My habilitation summarises the studies of fundamental properties of these particles within the Standard Model. In particular, I discuss both lifetime and mass measurements. This work is followed by a search of New Physics using a Lepton universality test. Finally, I discuss my contribution to the upgrade detectors of the LHCb experiment in particular those related to the calorimeter and the scintillator fibre tracker.
Observation in astronomy suggests that our Universe contains an abundance of matter over antimatter, which can only be explained if the combined CP symmetry is violated. Studies of CP violation have driven the flavor physics with the aim of testing the Standard Model of particle physics and searching for physics beyond. CP violation is discovered in strange, beauty and charm meson systems, however no conclusive sign of CP violation in baryon decays has been observed yet. This review summarizes CP violation studies performed by the LHCb experiment in charmless decays and rare decays of beauty b…
A model that can simultaneously explain Dark Matter relic density and the apparent matter anti-matter imbalance of the universe has been recently proposed. The model requires $b$-hadron branching fractions to Dark Matter at the per mille level. The $b$-hadrons decay to a dark sector baryon, $ψ_{\rm{DS}}$, which has a mass in the region $940$ MeV/c$^{2} \leq m(ψ_{\rm{DS}}) \leq 4430$ MeV/c$^{2}$. In this paper, we discuss the sensitivity of the LHCb experiment to search for this dark baryon, covering different types of topology and giving prospects for Runs 3 and 4 of the LHC, as well as for th…
We systematically study mass spectra and decay properties of $P$-wave $Ξ_c^\prime$ baryons of the $SU(3)$ flavor $\mathbf{6}_F$, using the methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. Our results suggest that the three excited $Ξ_c^0$ baryons recently observed by LHCb can be well explained as $P$-wave $Ξ_c^\prime$ baryons: the $Ξ_c(2923)^0$ and $Ξ_c(2939)^0$ are partner states of $J^P = 1/2^-$ and $3/2^-$ respectively, both of which contain one $λ$-mode orbital excitation; the $Ξ_c(2965)^0$ has $J^P = 3/2^-$, and also contains one $λ$-…
This paper describes an alternative method of charged hyperon reconstruction applicable to the LHCb experiment. It extends the seminal work of the FOCUS collaboration to the specific detector layout of LHCb and addresses the reconstruction ambiguities reported in their earlier work, leading to improvements in the reconstruction efficiency for the specific cases of Xi- and Omega- baryon decays to a charged meson and a Lambda baryon.
Inspired by the newly observed $Ω_c^0$ states at LHCb, we decode their properties by performing an analysis of mass spectrum and decay behavior. Our studies show that the five narrow states, i.e., $Ω_c(3000)^0$, $Ω_c(3050)^0$, $Ω_c(3066)^0$, $Ω_c(3090)^0$, and $Ω_c(3119)^0$, could be grouped into the $1P$ states with negative parity. Among them, the $Ω_c(3000)^0$ and $Ω_c(3090)^0$ states could be the $J^P=1/2^-$ candidates, while $Ω_c(3050)^0$ and $Ω_c(3119)^0$ are suggested as the $J^P=3/2^-$ states. $Ω_c(3066)^0$ could be regarded as a $J^P=5/2^-$ state. Since the the spin-parity, the electr…
New resonance $Λ_c(2860)^+$, reported by LHCb, is a key to establish \emph{D}-wave charmed and charmed-strange baryon families. In this work, we first carry out an analysis of mass spectra of the $λ$-mode excited charmed and charmed-strange baryon states, which may reveal the relation of $Λ_c(2860)^+$, $Λ_c(2880)^+$, $Ξ_c(3055)^+$ and $Ξ_c(3080)^+$, $i.e.$, $Λ_c(2860)^+$ and $Λ_c(2880)^+$ can form a \emph{D}-wave doublet $[3/2^+,5/2^+]$ while $Ξ_c(3055)^+$ and $Ξ_c(3080)^+$ are the strange partners of $Λ_c(2860)^+$ and $Λ_c(2880)^+$, respectively. Further study of their two-body Okubo-Zweig-Ii…
We perform a general SU(3)$_F$ analysis of $b\rightarrow c\bar{c}s(d)$ decays of members of the beauty baryon antitriplet to a member of the light baryon octet and a singlet. Under several reasonable assumptions we found $\left\vert \mathcal{A}(Ξ_b^0\rightarrow ΛS)/ \mathcal{A}(Ξ_b^0\rightarrow Ξ^0 S)\right\vert\approx 1/\sqrt{6}\, \left\vert V_{cb}^* V_{cd} / (V_{cb}^* V_{cs})\right\vert$ and $\left\vert\mathcal{A}(Λ_b\rightarrow Σ^0 S)/\mathcal{A}(Λ_b\rightarrow ΛS)\right\vert \sim 0.02$. These two relations have been recently probed by LHCb for the case of $S=J/ψ$. The former agrees with th…
Beauty baryons are being observed in large numbers in the LHCb detector. The rich kinematic distributions of their multibody decays are therefore becoming accessible and provide us with new opportunities to search for CP violation. We analyse the angular distributions of some three- and four-body decays of spin-$1/2$ baryons using the Jacob-Wick helicity formalism. The asymmetries that provide access to small differences of CP-odd phases between decay amplitudes of identical CP-even phases are notably discussed. The understanding gained on processes featuring specific resonant intermediate sta…
Though not considered in general, purely baryonic decays could shed light on the puzzle of the baryon number asymmetry in the universe by means of a better understanding of the baryonic nature of our matter world. As such, they constitute a yet unexplored class of decay processes worth investigating. We propose to search for purely baryonic decay processes at the LHCb experiment. No such type of decay has ever been observed. In particular, we concentrate on the decay $Λ_b^0\to p\bar pn$, which is the simplest purely baryonic decay mode, with solely spin-1/2 baryons involved. We predict its dec…
We study the four-body baryonic $B\to {\bf B_1 \bar B_2}M_1 M_2$ decays with $\bf B_{1,2}$ ($M_{1,2}$) being charmless baryons (mesons). In accordance with the recent LHCb observations, each decay is considered to proceed through the $B\to M_1 M_2$ transition together with the production of a baryon pair. We obtain that ${\cal B}(B^-\to Λ\bar p π^+π^-)=(3.7^{+1.5}_{-1.0} )\times 10^{-6}$ and ${\cal B}(\bar B^0\to p\bar p π^+π^-,p\bar p π^+ K^-)=(3.0\pm 0.9,6.6\pm 2.4)\times 10^{-6}$, in agreement with the data. We also predict ${\cal B}(B^-\toΛ\bar p K^+ K^-)=(3.0^{+1.3}_{-0.9})\times 10^{-6}$…
We study the bottom $Λ_b(6146)^0$ baryon, newly discovered by the LHCb Collaboration. By adopting an interpolating current of $(L_ρ, L_λ)=(0,2)$ type and $D$-wave nature with spin-parity quantum numbers $J^P=\frac{3}{2}^+$ for this heavy bottom baryon, we calculate its mass and residue. Using these spectroscopic parameters, we also investigate its dominant decays $Λ_b(6146)^0\rightarrowΣ_bπ$ and $Λ_b(6146)^0\rightarrowΣ^*_bπ$ and estimate the width of $Λ_b(6146)^0$ obtained via these channels. The obtained mass, $m_{Λ_b}=(6144\pm 68)$~MeV is in accord nicely with the experimental data. The wid…
Stimulated by recent progress made by the LHCb Collaboration in discoveries of new bottom baryons, e.g., the $Ξ_{b}(6227)^{-}$ and the $Σ_{b}(6097)^{\pm}$, we re-examine the orbitally excited spectrum of the charmed and bottom baryons using Regge approach in the heavy quark-diquark picture. The results indicate that the spin-averaged mass spectrum of the orbitally-excited charmed and bottom baryons can be described by a linear Regge relation, which is derived from the rotating QCD string model. By giving further mass-splitting analysis of spin-dependent interactions, we explain the baryons $Ξ_…
Selecting the newly observed $Ξ_b(6227)^-$ by LHCb as a study example, we decode its inner structure by giving the mass spectrum analysis and the investigation of its two-body strong decay behaviors. Our result indicates that the $Ξ_b(6227)^-$ is a good candidate of the $P$-wave $Ξ_b^{\prime}$ state with $J^P=3/2^-$ or $5/2^-$. In addition, we further provide the information of the properties of the partners of the $Ξ_b(6227)^-$. These predicted states include three $2S$ states and the remaining $1P$ states in the bottom-strange baryon family. The calculated sizable Okubo-Zweig-Iizuka$-$allowe…
Two bottom $Σ_b(6097)^\pm$ baryons were observed in the final states $Λ_b^0π^-$ and $Λ_b^0π^+$ in $pp$ collision by LHCb collaboration, whose masses and widths were measured. In a $^{3}P_{0}$ model, the strong decay widths of two ground $S$-wave and seven excited $P$-wave $Σ_b$ baryons have been systematically computed. Numerical results indicate that the newly observed $Σ_b(6097)^\pm$ are very possibly $Σ_{b2}^1({3\over 2}^-)$ with $J^P={3\over 2}^-$ or $Σ_{b2}^1({5\over 2}^-)$ with $J^P={5\over 2}^-$. The predicted decay widths of $Σ_b(6097)^\pm$ are consistent with experimental measurement …
LHCb has productive studies of quarkonia and $b$-hadrons which provide essential inputs to study quantum chromodynamics (QCD). In this proceeding, seven recent results are reported: the observation of a new excited $Ξ_b^0$ resonance in $Ξ_b^- π^+$ final states, the new excited $B_s^0$ state is observed in $B^+ K^-$ mass spectrum, the first observation of suppressed semileptonic $B_s^0 \rightarrow K^- μ^+ ν_μ$ decay, the first observation of the decay $B^0 \rightarrow D^0 \bar{D}^0 K^+ π^-$, the first observation of the Cabibbo-suppressed decay $Λ_b^0 \rightarrow χ_{c1} p π^-$, the first observ…
We study the $Λ_b(6146)^0$ and $Λ_b(6152)^0$ recently observed by LHCb using the method of QCD sum rules within the framework of heavy quark effective theory. Our results suggest that they can be interpreted as $D$-wave bottom baryons of $J^P = 3/2^+$ and $5/2^+$ respectively, both of which contain two $λ$-mode excitations. We also investigate other possible assignments containing $ρ$-mode excitations. We predict masses of their strangeness partners to be $m_{Ξ_b(3/2^+)} = 6.26^{+0.11}_{-0.14}$ GeV and $m_{Ξ_b(5/2^+)} = 6.26^{+0.11}_{-0.14}$ GeV with the mass splitting $ΔM = 4.5^{+1.9}_{-1.5}$…
The LHCb collaboration has presented first experimental evidence that spin-carrying matter and antimatter differ. The study looked at four-body decays of the $Λ_b^0$ baryon. Differences in the behaviour of matter and antimatter are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as $C\!P$ violation. We discuss purely baryonic decay processes, i.e. decay processes involving only spin-carrying particles. They are yet unexplored elementary processes. Their study opens a new chapter of flavour physics in the rou…
The LHCb Experiment at CERN has observed a doubly-charmed baryon $Ξ_{cc}^{++} =ccu$ with a mass of $3621.40 \pm 0.78$ MeV, consistent with many predictions. We use the same methods that led us to predict $M(Ξ_{cc},~J^P{=}1/2^+) = 3627 \pm 12$ MeV and $M(Ξ_{cc}^*,~J^P{=}3/2^+) = 3690 \pm 12$ MeV to predict $M(Ω_{cc}^+,J^P{=}1/2^+) = 3692 \pm 16$ MeV and $M(Ω_{cc}^*,~J^P{=} 3/2^+) = 3756 \pm 16$ MeV. Production and decay are discussed briefly, and predictions for $M(Ω_{bc})$ and $M(Ω_{bb})$ are included.
The LHCb experiment is dedicated to the study of the $c-$ and $b-$hadron decays, including long-lived particles such as $K_s$ and strange baryons ($Λ^0$, $Ξ^-$, etc... ). These kind of particles are difficult to reconstruct by the LHCb tracking system since they escape detection in the first tracker. A new method to evaluate the performance of the different tracking algorithms for long-lived particles using real data samples has been developed. Special emphasis is laid on particles hitting only part of the tracking system of the new LHCb upgrade detector.
In the present document a selected sample of the latest results on CP violation by the LHCb collaboration are presented. These include the first measurement of $ϕ_s^{c\overline{c}s} = 0.119 \pm0.107\pm0.034$ rad in a final state dominated by a tensor resonance, the most precise measurements of $C_{π^+π^-}$ and $S_{π^+π^-}$ to date, the first values ever measured of $C_{K^+K^-}$, $S_{K^+K^-}$ and $A_{K^+K^-}^{ΔΓ}$, the latest constraints on $γ= (76.8^{+5.1}_{-5.7})^\circ$ from the combination of several LHCb results and the first evidence for CP violation in baryonic mater at the level of 3.3$σ…
Recently the LHCb collaboration has observed a new pentaquark state, the $P_c(4337)^+$. Owing to its proximity to the $χ_{c0}(1S) p$, $\bar{D}^* Λ_c$, $\bar{D} Σ_c$ and $\bar{D} Σ_c^*$ thresholds, this new pentaquark might very well be a meson-baryon bound state. However its spin and parity have not been determined yet and none of the previous possibilities can be ruled out. We briefly explore a few of these options and the consequences they entail in the present manuscript: (i) the $P_c(4337)^+$ might be a $χ_{c0}(1S) p$ bound state, (ii) the $P_c(4312)^+$ and $P_c(4337)^+$ might be $\bar{D}^…
I review recent results on hadron spectroscopy using lattice QCD. In light of the discoveries in heavy baryon sector at LHCb over the past few years, lattice calculations in this regard are emphasized. Investigations on light baryon, heavy-heavy and heavy-light meson resonances are also discussed.
In this work, we calculate the branching ratios of the color-allowed two-body nonleptonic decays of the bottom baryons, which include the $Ξ_b\to Ξ_c^{(*)}$ and $Ω_b\to Ω_c^{(*)}$ weak transitions by emitting a pseudoscalar meson ($π^{-}$, $K^{-}$, $D^{-}$, and $D_s^{-}$) or a vector meson ($ρ^{-}$, $K^{*-}$, $D^{*-}$, and $D_s^{*-}$). For achieving this aim, we adopt the three-body light-front quark model with the support of hadron spectroscopy, where the spatial wave functions of these heavy baryons involved in these weak decays are obtained by a semirelativistic potential model associated w…
In the $B^+\to D^+ D^-K^+$ decay, LHCb has reported the observation of the open-charm exotic states $X_{0,1}^0\equiv X_{0,1}(2900)^0$ with four different quark flavors~$(ud\bar s \bar c)$, where the subscripts (0,1) denote the spins. To confirm the discovery, we propose $Λ_b\to Σ_c^{0(++)} X_{0,1}^{\prime\,0(--)}$ in the final state interaction, where $X_{0,1}^{\prime\,0(--)}$ with $s u\bar d \bar c$ ($ds\bar u \bar c$) are the new $X_{0,1}$-like exotic states. More specifically, $Λ_c^+D_s^-$ in $Λ_b\to Λ_c^+D_s^-$ are transformed as $Σ_c^{0(++)} X_{0,1}^{\prime\,0(--)}$, by exchanging $π^{+(-…
With a distinctive internal structure from all established hadrons, the beauty-charmed baryons $Ξ_{bc}$ can provide us with new points of view to decipher the strong interaction. In this work, we point out that the inclusive $Ξ_{bc} \to Ξ_{cc}^{++}+X$ decay is a golden channel for the experimental discovery of $Ξ_{bc}$ at the LHC. A unique feature of this process is that the $Ξ_{cc}^{++}$ is displaced, which greatly reduces the combinatorial background. A feasibility analysis is performed on the $Ξ_{bc}^+$ search, which is expected to have a longer lifetime than $Ξ_{bc}^0$ and thus a better di…
The LHCb Collaboration recently observed five narrow $Ω_c^{0}$ resonances, and measured their masses and widths through the decays $ Ω_c^{0} \to Ξ_c^{+}K^{-}$. Motivated by this discovery, and also by the fact that the ground-state bottom baryon $Ω_b^{-}$ with spin-1/2 was already found experimentally, we perform theoretical investigation of the spin-1/2 and spin-3/2, $Ω_b$, baryons by calculating decay width of their first orbitally and radially excited states to $Ξ_b^{0} K^{-}$. For this purpose, we employ QCD sum rule method on the light-cone by including into analysis the $K$ meson distrib…
We observe that four peaks seen in the high energy part of the $Ω_b$ spectrum of the recent LHCb experiment are in remarkable agreement with predictions made for molecular $Ω_b$ states stemming from the meson-baryon interaction, with an approach that applied to the $Ω_c$ states gave rise to three states in good agreement with experiment in masses and widths. While the statistical significance of the peaks prevents us from claims of states at the present time, the agreement found should be an incentive to look at this experiment with increased statistics to give an answer to this suggestive ide…
The physics potential for $b$-baryon decays has been relatively unexplored until the advent of the LHC, and as such important questions still exist about their fundamental properties, such as whether their decays exhibit $C\!P$ violation. Presented here are observations of the decays $Λ_b^0 \rightarrow ΛK^+π^-$ and $Λ_b^0 \rightarrow ΛK^+K^-$, made at a significance level of 8.1 and 15.8 Gaussian standard deviations, respectively, and measurements of their branching fractions. The phase-space integrated $C\!P$ asymmetries of these decays are also measured and found to be consistent with zero. …
The strong coupling constants of hadronic multiplets are fundamental parameters which carry information of the strong interactions among participating particles. These parameters can help us construct the hadron-hadron strong potential and gain information about the structure of the involved hadrons. Motivated by the recent observation of the doubly charmed $Ξ_{cc}$ state by LHCb, we determine the strong coupling constants among the doubly heavy spin-1/2 baryons, $ Ξ^{(\prime)}_{QQ^\prime }$, $ Ω^{(\prime)}_{QQ^\prime}$ and light pseudoscalar mesons, $ π$, $ K $, $η$ and $ η^\prime $ within th…
We have reviewed the renormalization procedure used in the unitarized coupled-channel model of Phys. Rev. D85 114032 (2012), and its impact in the $C=1$, $S=-2$, and $I=0$ sector, where five $Ω_c^{(*)}$ states have been recently observed by the LHCb Collaboration. The meson-baryon interactions used in the model are consistent with both chiral and heavy-quark spin symmetries and lead to a successful description of the observed lowest-lying odd parity resonances $Λ_c(2595)$ and $Λ_c(2625)$, and $Λ_b(5912)$ and $Λ_b(5920)$ resonances. We show that some (probably at least three) of the states obse…
We study the $C=1$, $S=-2$, $I=0$ sector, where five excited $Ω_c$ states have been recently observed by the LHCb Collaboration. We start from a recently developed unitarized baryon-meson model that takes, as bare baryon-meson interaction, an extended Weinberg-Tomozawa kernel consistent with both chiral and heavy-quark spin symmetries. This ${\rm SU(6)} \times {\rm HQSS}$ scheme leads to a successful description of the observed lowest-lying odd parity charmed $Λ_c$(2595) and $Λ_c$(2625) states, and bottomed $Λ_b$(5912) and $Λ_b$(5920) resonances. Within this model, five odd-parity $Ω_c$ states…
