We study singly Cabibbo-suppressed two-body hadronic decays of the charmed baryon Λ þ c , namely,We use the measured rate of Λ þ c → pϕ to fix the effective Wilson coefficient a 2 for naive color-suppressed modes and the effective number of color N eff c . We rely on the current-algebra approach to evaluate W-exchange and nonfactorizable internal W-emission amplitudes, that is, the commutator terms for the S wave and the pole terms for the P wave. Our prediction for Λ þ c → pη is in excellent agreement with the BESIII measurement. The pη (pπ 0 ) mode has a large (small) rate because of a large constructive (destructive) interference between the factorizable and nonfactorizable amplitudes for both S and P waves. Some of the SU(3) relations such asMðΛ þ c → pπ 0 Þ derived under the assumption of sextet dominance are not valid for decays with factorizable terms. Our calculation indicates that the branching fraction of Λ þ c → nπ þ is about 3.5 times larger than that of Λ þ c → pπ 0 . Decay asymmetries are found to be negative for all singly Cabibbo-suppressed modes and range from −0.56 to −0.96.

We study Cabibbo-favored (CF) and singly Cabibbo-suppressed (SCS) two-body hadronic weak decays of the antitriplet charmed baryons Λ + c , Ξ 0 c and Ξ + c with more focus on the last two. Both factorizable and nonfactorizable contributions are considered in the topologic diagram approach. The estimation of nonfactorizable contributions from W -exchange and inner W -emission diagrams relies on the pole model and current algebra. The non-perturbative parameters in both factorizable and nonfactorizable parts are calculated in the MIT bag model. Branching fractions and up-down decay asymmetries for all the CF and SCS decays of antitriplet charmed baryons are presented. The prediction of B(Ξ + c → Ξ 0 π + ) agrees well with the measurements inferred from Belle and CLEO, while the calculated B(Ξ 0 c → Ξ − π + ) is too large compared to the recent Belle measurement. We conclude that these two Ξ c → Ξπ + modes cannot be simultaneously explained within the current-algebra framework for S-wave amplitudes. This issue needs to be resolved in future study. The long-standing puzzle with the branching fraction and decay asymmetry of Λ + c → Ξ 0 K + is resolved by noting that only type-II W -exchange diagram will contribute to this mode. We find that not only the calculated rate agrees with experiment but also the predicted decay asymmetry is consistent with the SU(3)-flavor symmetry approach in sign and magnitude. Likewise, the CF mode Ξ 0 c → Σ + K − and the SCS decays Ξ 0 c → pK − , Σ + π − proceed only through type-II W -exchange. They are predicted to have large and positive decay asymmetries. These features can be tested in the near future. a fanrongxu@jnu.edu.cn c receive nonfactorizable contributions, especially some decays such as Ξ 0 c → Σ + K − , Ξ 0 π 0 proceed only through purely nonfactorizable diagrams, will allow us to check the importance and necessity of nonfactorizable contributions. However, we still do not have a reliable phenomenological model to calculate charmed baryon hadronic decays so far. In the 1990s various techniques were developed, including relativistic quark model (RQM) [20,21], pole model [22][23][24] and current algebra [23,25], to estimate the nonfactorizable effects in Cabbibo-favored Ξ +,0 c decays. The predicted branching fractions and

We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector can achieve a better than 1% energy linearity and a 3% effective energy resolution, required by the neutrino mass ordering determination.

The Jiangmen Underground Neutrino Observatory (JUNO) features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector. Some of JUNO's features make it an excellent location for B solar neutrino measurements, such as its low-energy threshold, high energy resolution compared with water Cherenkov detectors, and much larger target mass compared with previous liquid scintillator detectors. In this paper, we present a comprehensive assessment of JUNO's potential for detecting B solar neutrinos via the neutrino-electron elastic scattering process. A reduced 2 MeV threshold for the recoil electron energy is found to be achievable, assuming that the intrinsic radioactive background U and Th in the liquid scintillator can be controlled to 10 g/g. With ten years of data acquisition, approximately 60,000 signal and 30,000 background events are expected. This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter, which will shed new light on the inconsistency between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework. If eV , JUNO can provide evidence of neutrino oscillation in the Earth at approximately the 3 (2 ) level by measuring the non-zero signal rate variation with respect to the solar zenith angle. Moreover, JUNO can simultaneously measure using B solar neutrinos to a precision of 20% or better, depending on the central value, and to sub-percent precision using reactor antineutrinos. A comparison of these two measurements from the same detector will help understand the current mild inconsistency between the value of reported by solar neutrino experiments and the KamLAND experiment.

The LHCb experiment observed B + → π + µ + µ − decay with 1.0 fb −1 data, which is the first measurement of a flavor changing neutral current b → dℓ + ℓ − decay (ℓ = e, µ). Based on QCD factorization, we give Standard Model predictions for the branching ratios, direct CP asymmetries, and isospin asymmetry for B → πℓ + ℓ − decays, in the kinematic region where the dilepton invariant mass is small. We find that the contribution from weak annihilation enhances the direct CP asymmetry for low ℓ + ℓ − pair mass. Anticipating improved measurements, we assess the utility offor determining CKM parameters in the future. PACS numbers: 12.15.Hh 11.30.Er 13.20.He 1 As for B → K ( * ) ℓ + ℓ − /ρℓ + ℓ − , isospin asymmetries were also are of great interest even within SM because V * ud V ub carries CPV phase. In contrast, such effects are suppressed by V * us V ub for b → sℓ + ℓ − processes. The B → πℓ + ℓ − modes may also be used to probe New Physics, such as two Higgs doublet model [4, 5], R-parity violating supersymmetry [6], and fourth generation [18].This paper is a followup of the last paper, where some results were used in conjunction with the study of B d → µ + µ − mode. In this paper we focus on SM expectations for B → πℓ + ℓ − . After presenting the basic formulas and input parameters in Sec. II, the SM predictions are given in Sec. III. We discuss prospects for constraining CKM parameters in Sec. IV, before giving our conclusion. Some details are placed in Appendices. studied [16] employing light-cone sum rule to calculate matrix elements for weak annihilation and O 8 [in Eq. (4)] [17].