Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userStudy of the $D^0 p$ amplitude in $Lambda_b^0to D^0 p pi^-$ decays
128
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
An amplitude analysis of the decay $Lambda_b^0to D^0 p pi^-$ is performed in the part of the phase space containing resonances in the $D^0 p$ channel. The study is based on a data sample corresponding to an integrated luminosity of 3.0 fb$^{-1}$ of $pp$ collisions recorded by the LHCb experiment. The spectrum of excited $Lambda_c^+$ states that decay into $D^0 p$ is studied. The masses, widths and quantum numbers of the $Lambda_c(2880)^+$ and $Lambda_c(2940)^+$ resonances are measured. The constraints on the spin and parity for the $Lambda_c(2940)^+$ state are obtained for the first time. A near-threshold enhancement in the $D^0 p$ amplitude is investigated and found to be consistent with a new resonance, denoted the $Lambda_c(2860)^+$, of spin $3/2$ and positive parity.
rate research
Read More
Charm meson oscillations are observed in a time-dependent analysis of the ratio of $D^0to K^+pi^-pi^+pi^-$ to $D^0to K^-pi^+pi^-pi^+$ decay rates, using data corresponding to an integrated luminosity of $3.0,{rm fb}^{-1}$ recorded by the LHCb experiment. The measurements presented are sensitive to the phase-space averaged ratio of doubly Cabibbo-suppressed to Cabibbo-favoured amplitudes $r_{D}^{K3pi}$ and the product of the coherence factor $R_{D}^{K3pi}$ and a charm mixing parameter $y^{}_{K3pi}$. The constraints measured are $r_{D}^{K3pi}=(5.67 pm 0.12)times10^{-2}$, which is the most precise determination to date, and $R_{D}^{K3pi} cdot y^{}_{K3pi} = (0.3 pm 1.8)times 10^{-3}$, which provides useful input for determinations of the CP-violating phase $gamma$ in $B^pm to D K^pm, D to K^mppi^pmpi^mppi^pm$ decays. The analysis also gives the most precise measurement of the $D^0to K^+pi^-pi^+pi^-$ branching fraction, and the first observation of $D^0-bar D^0$ oscillations in this decay mode, with a significance of 8.2 standard deviations.
Asymmetries in the time-dependent rates of $D^0 to K^+K^-$ and $D^0 to pi^+pi^-$ decays are measured in a $pp$ collision data sample collected with the LHCb detector during LHC Run 1, corresponding to an integrated luminosity of $3,mathrm{fb}^{-1}$. The asymmetries in effective decay widths between $D^0$ and $overline{D}^0$ decays, sensitive to indirect $CP$ violation, are measured to be $A_Gamma(K^+ K^-) = (-0.30 pm 0.32 pm 0.10)times 10^{-3}$ and $A_Gamma(pi^+pi^-) = (0.46 pm 0.58 pm 0.12)times 10^{-3}$, where the first uncertainty is statistical and the second systematic. These measurements show no evidence for $C!P$ violation and improve on the precision of the previous best measurements by nearly a factor of two.
We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of $D^0to K^+pi^-$ to $D^0to K^-pi^+$ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of $5.0$ fb$^{-1}$ recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be $x^2=(3.9 pm 2.7) times10^{-5}$, $y=(5.28 pm 0.52) times 10^{-3}$, and $R_D=(3.454 pm 0.031)times10^{-3}$. Without this assumption, the measurement is performed separately for $D^0$ and $overline{D}{}^0$ mesons, yielding a direct CP-violating asymmetry $A_D =(-0.1pm9.1)times10^{-3}$, and magnitude of the ratio of mixing parameters $1.00< |q/p| <1.35$ at the $68.3%$ confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed.
The Dalitz plot distribution of $B^0 rightarrow bar{D}^0 K^+ pi^-$ decays is studied using a data sample corresponding to $3.0rm{fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate $K^*(892)^0$, $K^*(1410)^0$, $K^*_2(1430)^0$ and $D^*_2(2460)^-$ resonances. The model also contains components to describe broad structures, including the $K^*_0(1430)^0$ and $D^*_0(2400)^-$ resonances, in the $Kpi$ S-wave and the $Dpi$ S- and P-waves. The masses and widths of the $D^*_0(2400)^-$ and $D^*_2(2460)^-$ resonances are measured, as are the complex amplitudes and fit fractions for all components included in the amplitude model. The model obtained will be an integral part of a future determination of the angle $gamma$ of the CKM quark mixing matrix using $B^0 rightarrow D K^+ pi^-$ decays.
Recently we derived a nonlinear U-spin amplitude relation for $D^0to P^+P^-$, $P=pi, K$, predicted to hold up to fourth order U-spin breaking terms of order $10^{-3}$. Here we study a similar relation for $D^0to V^+P^-, V =rho, K^*(892), P = pi, K$, expected to hold at an even higher accuracy of order $10^{-4}$. We confirm this prediction in spite of a large experimental error of about 20% in the amplitude of $D^0to K^{*+}pi^-$. We also comment briefly on U-spin breaking in $D^0to P^+V^-$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
