LHCb continues to expand its world-leading sample of charmed hadrons collected during LHC's Run 1 (2010-2012) and Run 2 (2015-present). This sample is yielding some of the most stringent tests of the Standard Model understanding of charm physics. This includes precise measurements of the neutral D-meson mixing parameters and some of the most sensitive searches for direct and indirect CP violation in charm interactions.
This document presents eight recent and new analyses from the LHCb experiment covering results on CKM angle $γ$ and high precision measurements on charm mixing parameters. In addition, the latest CP violation measurements in charm and beauty decays are reported.
Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is poised to become a world leading experiment for charm studies, recording enormous statistics with a detector tailored for flavor physics. This article presents recent charm CPV and mixing studies from LHCb, including LHCb's first CP asymmetry measurement with 37 inverse pb of data collected in 2010. The difference of the CP asymmetries of D0 decays to the K-K+ and π-π+ final states is determined to be ΔA_{CP} = (-0.28 +/- 0.70 +/- 0.25)%. Significant updates to the materia…
The Standard Model predicts CP asymmetries in charm decays of $O(10^{-3})$ and the observation of significantly larger CP violation could indicate non-Standard Model physics effects. During 2011 and 2012, the LHCb experiment collected a sample corresponding to 3/fb yielding the world's largest sample of decays of charmed hadrons. This allowed the CP violation in charm to be studied with unprecedented precision in many two- body and multibody decay modes. The most recent LHCb searches for direct CP violation are presented in these proceedings.
In these proceedings, recent results on time-dependent and time-integrated measurements of $C\!P$ violation and of meson mixing in the charm sector are presented, including the first observation of $C\!P$ violation in the charm system.
LHCb has collected the world's largest sample of charmed hadrons. This sample is used to search for direct and indirect CP violation in charm and to measure $D^0$ mixing parameters. Preliminary measurements from several decay modes are presented, with complementary time-dependent and time-integrated analyses.
Very recently, the LHCb Collaboration observed the $CP$ violation (CPV) in the charm sector for the first time, with $ΔA_{CP}^{\rm dir}\equiv A_{CP}(D^0\to K^+K^-)-A_{CP}(D^0\to π^+π^-)=(-1.54\pm0.29)\times10^{-3}$. This result is consistent with our prediction of $ΔA_{CP}^{\rm SM}=(-0.57\sim -1.87)\times 10^{-3}$ obtained in the factorization-assisted topological-amplitude (FAT) approach in [PRD86,036012(2012)]. It implies that the current understanding of the penguin dynamics in charm decays in the Standard Model is reasonable. Motivated by the success of the FAT approach, we further suggest…
An overview of the recent first observation of CP violation in the Charm sector by the LHCb collaboration. Selection of theoretical models explaining this measurement is reviewed. Finally, experimental prospects for future measurements are discussed.
A first measurement of \fplus, the \CP-even content of the decay D->4pi using decays of $ψ(3770)$ to quantum correlated $D\bar{D}$ decays collected by the CLEO-c experiment is presented. The measured value is \fplus=$0.737 \pm 0.028$. This relatively high value makes the decay mode particularly suitable for both measurements of the CKM angle $γ$ and charm \CP-violation in a model independent way. This novel approach to studying indirect \CP-violation in charm decays is based on the time-dependent inclusive analysis of multi body self-conjugate states. These final states can be used to determin…
We review basic phenomenology on $D^0$ mixing/CP violation and recent experimental results on them. $D^0$ mixing is established by combining results from multiple experiments but no CP violation in the charm sector has been seen. $D^0$ mixing from a single experiment will clarify the size of the mixing, and observation of CP violation in charm decays at the present level of experimental sensitivity would be clear signal of new physics beyond the standard model.
The LHCb experiment has measured CP violation (CPV) across the Dalitz plot of charmless decays of B+ mesons to 3 charged tracks, namely in Kππ, KKK, πππ and πKK final states, with strikingly large CPV that vary strongly with Dalitz variables. Identifying these processes with b -> sqq(bar), sss(bar) and b -> dqq(bar), dss(bar), where q = u, d, then the "sum rule" that requires two-loop absorptive parts by unitarity works well for inclusive b -> s CPV, but less well for inclusive b -> d case. We elucidate the situation, and argue that the 30 year old unitarity/CPT argument is valid to this day, …
CP violation (CPV) in the baryon sectors has not yet been established experimentally. In this work, we propose to search for the hyperon CPV through the Cabibbo-favored charm-baryon decaying processes involving a hyperon in the final states, such as $Λ_c^+\to Λ^0π^+, Λ^0\to pπ^-$. The CPV of the hyperon decays are purely revealed in these chain processes, since the CPV in the Cabibbo-favored charm decays are vanishing in the Standard Model (SM). The hyperons are polarized in the weak charm decays, so that we can measure the Lee-Yang asymmetric parameter $α$ by the angular distributions, and th…
Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is poised to become a world leading experiment for charm physics, recording enormous samples with a detector tailored for flavor physics. This article presents recent charm production, CPV, and mixing studies from LHCb, including LHCb's first charm CP asymmetry measurement with 37 pb^-1 of data collected in 2010.
We see copious production of charmed hadrons in the early LHCb data. The status and plans for charm production studies at LHCb are discussed, and preliminary signals are shown.
Charm physics has been established at the LHC based on several high-precision measurements. The future of charm physics at the LHC experiments is discussed in detail. The bulk of the charm physics programme will be performed by LHCb and the LHCb upgrade. In particular, the impact of the LHCb upgrade on mixing and \CP violation measurements is presented.
This proceeding contribution presents the latest measurement of the CP-violation and other physics parameters in the $B_s^0 \to J/ψϕ$ decay channel performed by the ATLAS, CMS and LHCb experiments. The measurements are based on a data set collected at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. Besides the CP violating phase $ϕ_s$, the width difference between the $B_{s}^0$ meson mass eigenstates $ΔΓ_s$ and the average decay width $Γ_s$ are measured. The measured values are then combined with those collected at 8 TeV. The measurements are consistent with theoretic…
LHCb has collected the world's largest sample of charmed hadrons. This sample is used to search for direct and indirect CP Violation in charm. Recent and updated measurements from several decay modes are presented.
Recent charm spectroscopy results from Dalitz plot analyses of $B$ decays to open charm final states at LHCb are presented. The decay modes used are $B^{+} \to D^{-} K^{+} π^{+}$, $B^{0} \to \overline{D}{}^{0} π^{+} π^{-}$ and $B^{0} \to \overline{D}{}^{0} K^{+} π^{-}$.
Studies of charm physics with the 2010 LHCb data sample are presented. Time-integrated searches for CP violation in D+ -> K- K+ pi+ and D0 -> K- K+, pi- pi+ are discussed.
Studies of rare decays are an indirect probe of New Physics (NP). This document presents recent measurements of rare decays in the charm sector by the LHCb experiment. The analyses are performed with proton-proton collision data at $\sqrt{s}$ = 7 TeV recorded in 2011.
We present recent results from charmonium and open charm production at the LHCb experiment at CERN, Geneva. We concentrate on studies for the measurement of the cross section pp ->JPsi+X in its decay channel with two muons, showing the agreement of the simulation with the data in few key distributions. We also show the reconstructed modes of D0->K-pi+, D0 K-pi+pi0, LambdaC+ -> p K-pi+ and D+ ->Ks0 pi+ and their prospects.
The study of charmless b-hadron decays provides information for testing the CKM picture of CP violation in the Standard Model. In addition, as they can proceed through loop diagrams, they are also sensitive to physics beyond the Standard Model. A review of recent results from LHCb on charmless b-hadron decays is presented.
The LHCb experiment has been able to collect the largest sample ever produced of charm-hadron decays, performing a number of measurements of observables related to $C\!P$ violation in the charm sector. In this document, the most recent results from LHCb on the search of direct $C\!P$ violation in $D^0 \to K_s^0 K_s^0$, $D_{(s)}^+ \to h^+ π^0$ and $D_{(s)}^+ \to h^+ η$ decays are summarised, in addition to the most precise measurement of time-dependent $C\!P$ asymmetry in $D^0 \to h^+ h^-$ decays and the first observation of mass difference between neutral charm-meson eigenstates.
Two measurements of mixing and $CP$ violation in charm decays performed at the LHCb experiment are presented. The former is a measurement of the mixing observable $y_{CP}-y_{CP}^{Kπ}$ in two-body $D^0$ decays, while the latter is a search for direct $CP$ violation in $D^+_{(s)}\rightarrowη^{(')}π^+$ decays.
We present a summary of new experimental results on the status of the charm spectroscopy using inclusive approaches and Dalitz plot analyses of $B$ and $B_s$ decays. We also report on a new determination of the $X(3872)$ quantum numbers.
During run I, the LHCb experiment at the LHC, CERN, collected 1.0 fb$^{-1}$ of pp collisions at $\sqrt{s} = 7$ TeV and 2.0 fb$^{-1}$ at $\sqrt{s} = 8$ TeV, yielding the world's largest sample of decays of charmed hadrons. This sample is used to search for direct and indirect CP violation in charm and to measure $D^{0}$ mixing parameters. Recent measurements from several complementary decay modes are presented.
The LHCb experiment has collected the world's largest sample of charmed hadrons. This sample is used to measure observables related to $D^0 -\overline{D}^0$ mixing, direct $C\!P$ violation and $C\!P$ violation in mixing and interference in the charm sector. In this document, the most recent results from LHCb on the search of direct $C\!P$ violation in $D^0$ and $D_{(s)}^+$ decays are summarised, as well as the first observation of mass difference between neutral charm-meson eigenstates and the most precise measurement of time-dependent $C\!P$ asymmetry in $D^0 \to K^+ K^-$ and $D^0 \to π^+ π^-…
LHCb has started its charm physics programme using the data taken at the LHC. The first measurements of open charm production cross-sections for proton proton collisions at $\sqrt{s}=7 \tev$ are presented. The cross-sections of the \PDzero, $\PDstar^+$, \PDplus, and \PDsplus mesons are found to be in broad agreement with theory predictions. The prospects for measurements of charm mixing, CP and T violation in decays of neutral \PD mesons at LHCb are discussed. Furthermore, plans for CP violation measurements using charged \PD mesons are presented. Most analyses are expected to yield results im…
Recent measurements of mixing and $CP$ violation in charm decays at LHCb are presented. These include searches for direct $CP$ violation in $D^{0}\rightarrow K_{S}^{0}K_{S}^{0}$, $D_{(s)}^{+}\rightarrow h^{+} π^{0} $ and $D_{(s)}^{+}\rightarrow h^{+}η$ decays, and a search for time-dependent $CP$ violation in $D^{0}\rightarrow h^{+}h^{-}$ decays, where $h^{+}$ is either a $π^{+}$ or $K^{+}$ meson.
Following the intriguing hints of deviations from the Standard Model in rare B meson decays, searches for rare and forbidden decays of charm hadrons become a hot topic again. We present recent results on Flavour Changing Neutral Current $D^{0}\rightarrowμ^+ μ^-$, $D^0 \rightarrowμ^+μ^- π^+ π^-$, $D^{\pm}_{(s)}\rightarrow π^{\pm} μ^+μ^-$ and LFV $D^{\pm}_{(s)}\rightarrow π^{\mp}μ^{\pm}μ^{\pm}$ obtained at LHCb.
The LHCb experiment has opened the possibility to test mixing and $C\!P$ violation in the charm sector with unprecedented precision thanks to the huge number of charm hadron decays collected, $\mathcal{O}(10^8)$. The first observation of $C\!P$ violation in the decay of charm quarks in March 2019 has been a fundamental achievement. The latest LHCb measurements in the complementary sectors of mixing and time-dependent $C\!P$ violation are illustrated in these proceedings. In particular, a new measurement of the $C\!P$ violation parameter $A_Γ$ with 2015--2016 data that was presented for the fir…
We present studies from the LHCb experiment of decays of the type H_b to H_c X, where H_b represents a beauty hadron (B+, B0 or Lambda_b) and H_c a charmed hadron (D0, D(*)+, Ds or Lambda_c). Such decays are important for the determination of the CKM angle gamma, a key goal of the LHCb physics programme. We exploit the data accumulated in 2010, and in the early months of the 2011 run. We report on the observation of new decay modes, and first measurements on the road to a precise determination of gamma.
LHCb is a dedicated flavor physics experiment that will observe the 14 TeV proton-proton collisions at CERN's Large Hadron Collider (LHC). Construction of the LHCb detector is near completion, commissioning of the detector is well underway, and LHCb will be fully operational and ready to take data in advance of the projected May 2008 turn-on date for the LHC. The LHCb software trigger will feature a dedicated channel for events containing D* mesons that will dramatically enhance the statistical reach of LHCb in many charm physics measurements. The LHCb charm physics program is initially focuse…
The LHCb experiment collected during run I the world's largest sample of charmed hadrons. This sample is used to search for CP violation in charm and for the measurements of D0 mixing parameters. The measurement of the D0 to D0bar mixing parameters and the search for indirect CP-violation in two-body charm decays at LHCb experiment are presented.
The LHCb experiment has fully reconstructed close to 10^9 charm hadron decays---by far the world's largest sample. During the 2011-2012 running periods, the effective proton-proton beam crossing rate was 11-15 MHz while the rate at which events were written to permanent storage was 3-5 kHz. Prompt charm candidates (produced at the primary interaction vertex) were selected using a combination of exclusive and inclusive high level (software) triggers in conjunction with low level hardware triggers. The efficiencies, background rates, and possible biases of the triggers as they were implemented w…
We report a measurement of the time-dependent ratio of $D^0\to K^+π^-$ to $D^0\to K^-π^+$ decay rates in $D^{*+}$-tagged events using 1.0\,fb$^{-1}$ of integrated luminosity recorded by the LHCb experiment. We measure the mixing parameters $x'^2=(-0.9\pm1.3)\times10^{-4}$, $y'=(7.2\pm2.4)\times10^{-3}$ and the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates $R_D=(3.52\pm0.15)\times10^{-3}$. The result excludes the no-mixing hypothesis with a probability corresponding to 9.1 standard deviations and represents the first observation of charm mixing from a single measurement
Recent results on mixing, CP violation and rare decays in charm physics from the LHCb experiment are presented. Study of ''wrong-sign'' $D^{0} \rightarrow K^+ π^-$ decays provides the highest precision measurements to date of the mixing parameters $x^{\prime 2}$ and $y^{\prime}$, and of CP violation in this decay mode. Direct and indirect CP violation in the $D^0$ system are probed to a sensitivity of around $10^{-3}$ using $D^0 \rightarrow K^+K^-$ and $D^0 \rightarrow π^+π^-$ decays and found to be consistent with zero. Searches for the rare decays $D^+_{(s)} \rightarrow π^+μ^+μ^-$, $D^+_{(s)…
LHCb has a rich programme studying hadronic B-decays and is already showing that with early data it can produce precision measurements which improve on current world averages. The preliminary results presented include the new world's best measurements of the Acp(Bd -> K+ pi-) = -0.088 +/- 0.011 (stat) +/- 0.008 (syst) and tau(Bs -> K+ K-) = 1.440 +/- 0.096 (stat) +/- 0.010 (syst) ps. These were obtained using the full 2010 data sample containing 37 pb-1 and also 320 pb-1 of the 2011 data. The first observation of CP violation in Bs -> pi+ K- is also presented.
Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is well equipped to take advantage of the enormous production cross-section of charm mesons in $pp$ collisions at $\sqrt{s}=7$ TeV. The measurement of the $D^0 -\bar{D}^0$ mixing parameters and the search for CP-violation in the charm sector are key physics goals of the LHCb programme. The first CP violation measurements in the charm sector, with 37 pb$^{-1}$ of data collected in 2010, are discussed. The study of $D^+ \rightarrow K^- K^+ π^+$ decays shows no indication of CP …
Amplitude analysis is a powerful tool to study the properties of intermediate resonances produced in the decays of B mesons. At LHCb we have studied B+ decays to X(3872) K+, where X(3872) decays to J/psi pi+ pi-, to determine the quantum numbers of the X(3872), and B+ decays to proton anti-proton K+ to learn more about (charm anti-charm) to proton anti-proton transitions. We also exploit the spin of the J/psi to perform amplitude analyses of the decays B0_s to J/psi pi+ pi-, B0_s to J/psi K+ K-, B0 to J/psi pi+ pi-, and B0 to J/psi K+ K-. Our results use 1.0 inverse femtobarn of data taken in …
High-precision measurements performed by the LHCb collaboration have opened a new era in charm physics. Several crucial measurements, particularly in spectroscopy, rare decays and CP violation, can benefit from the increased statistical power of an upgraded LHCb detector. The upgrade of LHCb detector, its software infrastructure, and the impact on charm physics are discussed in detail.
Charmless B hadrons decays offer rich opportunities to test the Standard Model. CP violation in charmless charged two-body and three-body B decays provides ways to measure the CKM angle $γ$ and to search for New Physics. Also, vector-vector final states provide additional interesting observables. Hereby, we present the latest LHCb results on hadronic charmless B decays putting emphasis on the direct CP violation measurements.
LHCb collaboration measured CPV at the level of one percent in the difference of assymetries in $D^0(\bar D^0)\to π^+ π^-, K^+ K^-$ decays. If confirmed on a larger statistics and final systematics this would mean New Physics manifestation. The fourth quark-lepton generation can be responsible for the observed effect.
The beauty hadron decays is unique laboratory to study charmonium and charmonium-like states, such as the $χ_{c1}(3872)$ meson, other exotic states and the tensor D-wave $ψ_2(3823$) states. However the nature of many exotic charmonium-like candidates are still unknown. The most recent LHCb results related to b-hadron decays to charmonium states and obtained using large data samples collected during the Run 1 and Run 2 periods are presented. This includes the most precise determination of the mass and width of the $χ_{c1}(3872)$ state using the $B^{+} \to J/ψπ^{+}π^{-}K^{+}$ decays, observation…
We present a brief review of CPV and mixing measurements in the charm sector, with emphasys in results published or presented since the previous edition of the Physics in Collision Symposia.
A search for charge-parity (CP) violation in $D^0 \to K^- K^+$ and $D^0 \to π^-π^+$ decays is reported, using $pp$ collision data corresponding to an integrated luminosity of 5.9 $\mathrm{fb}^{-1}$ collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the $D^0$ meson is determined from the charge of the pion in $D^*(2010)^+ \to D^0 π^+$ decays or from the charge of the muon in $\kern 0.18em\overline{\kern -0.18em B}{} \to D^0 μ^- \barν_μX$ decays. The difference between the CP asymmetries in $D^0 \to K^- K^+$ and $D^0 \to π^-π^+$ decays is measured to be $ΔA_{\rm…
Rare heavy flavor decays are an ideal place to search for the effects of potential new particles that modify the decay rates or the Lorentz structure of the decay vertices. The LHCb experiment, a dedicated heavy flavour experiment at the LHC at CERN. It has recorded the worlds largest sample of heavy meson and lepton decays. The status of the rare decay analyses with 1\,fb$^{-1}$ of $\sqrt s = 7\,$TeV and 1.1\,fb$^{-1}$ of $\sqrt s = 8\,$TeV of $pp$--collisions collected by the LHCb experiment in 2011 and 2012 is reviewed. The worlds most precise measurements of the angular structure of $B^0\r…
LHCb is a dedicated heavy flavour physics precision experiment at the LHC searching for New Physics (NP) beyond the Standard Model (SM) through the study of very rare decays of beauty and charm-flavoured hadrons and precision measurements of CP-violating observables. In this review I will present a selection of recent precision measurements of CP-violating observables in the decays of beauty and charm-flavoured hadrons. These measurements are based on an integrated luminosity of up to $1.0 \rm{fb}^{-1}$ collected by LHCb in 2011.
A study of $D^+π^-$, $D^0 π^+$ and $D^{*+}π^-$ final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 $fb^{-1}$, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The $D_1(2420)^0$ resonance is observed in the $D^{*+}π^-$ final state and the $D^*_2(2460)$ resonance is observed in the $D^+π^-$, $D^0 π^+$ and $D^{*+}π^-$ final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 280…
In these proceedings, we explore the possible reach of the LHCb dataset in the area of charm semileptonic decays. Specifically, we give prospects for the measurement of $|V_{cs}|/|V_{cd}|$ using $\mathcal{B}(D^0\to K^-μ^+ν_μ)/\mathcal{B}(D^0\toπ^-μ^+ν_μ)$ with Run I data. Preliminary projections show that the LHCb Run I dataset would give a relative statistical uncertainty of $\sim 0.2\%$ on this ratio. We also motivate the search for lepton non-universality in the charm sector.
Rare decays of beauty and charm hadrons offer a rich playground to make precise tests of the Standard Model and look for New Physics at the level of quantum corrections. A review of recent LHCb results will be presented.
At LHCb, proton parton distribution functions (PDFs) can be studied in a unique phase space complementary to that accessible by ATLAS and CMS, corresponding to low and high values of Bjorken-$x$. The measurements of vector boson production in the forward region, with and without an associated jet, are presented. These measurements can be used to constrain the proton PDFs, and in particular, the production of a $Z$ boson in association with a $c$-jet can be studied to measure the intrinsic charm content of the proton.
