arXiv subjects

P. Y. Lin

Publications and source records attributed to P. Y. Lin.

5 recordsLinked to original sources

arXiv2015

Charmful two-body anti-triplet $b$-baryon decays

We study the charmful decays of the two-body ${\cal B}_b\to {\cal B}_n M_c$ decays, where ${\cal B}_b$ represents the anti-triplet of $(Λ_b,Ξ_b^0,Ξ_b^-)$, ${\cal B}_n$ stands for the baryon octet and $M_c$ denotes as the charmed meson of $D^{(*)}_{(s)}$, $η_c$ and $J/ψ$. Explicitly, we predict that ${\cal B}(Λ_b\to D_s^- p)=(1.8\pm 0.3)\times 10^{-5}$, which is within the measured upper bound of ${\cal B}(Λ_b\to D_s^- p)<4.8(5.3)\times 10^{-4}$ at 90\%\,(95\%) C.L., and reproduce ${\cal B}(Λ_b\to J/ψΛ)=(3.3\pm 2.0)\times 10^{-4}$ and ${\cal B}(Ξ_b^-\to J/ψΞ^-)=(5.1\pm 3.2)\times 10^{-4}$ in agreement with the data. Moreover, we find that ${\cal B}(Λ_b \to Λη_c)=(1.5 \pm 0.9) \times 10^{-4}$, ${\cal B}(Ξ_b^-\toΞ^-η_c)=(2.4\pm1.5) \times 10^{-4}$ and ${\cal B}(Ξ_b^0\toΞ^0η_c,Ξ^0 J/ψ)=(2.3\pm1.4,4.9\pm3.0)\times 10^{-4}$, which are accessible to the experiments at the LHCb.

hep-ph↗

arXiv2015

Fragmentation fractions of two-body b-baryon decays

We study the fragmentation fractions $(f_{{\bf B}_b})$ of the $b$-quark to b-baryons (${\bf B}_b$). By the assumption of $f_{Λ_b}/(f_u+f_d)=0.25\pm 0.15$ in accordance with the measurements by LEP, CDF and LHCb Collaborations, we estimate that $f_{Λ_b}=0.175\pm 0.106$ and $f_{Ξ_b^{-,0}}=0.019\pm 0.013$. From these fragmentation fractions, we derive ${\cal B}(Λ_b\to J/ψΛ)=(3.3\pm 2.1)\times 10^{-4}$, ${\cal B}(Ξ_b^-\to J/ψΞ^-)=(5.3\pm 3.9)\times 10^{-4}$ and ${\cal B}(Ω_b^-\to J/ψΩ^-)>1.9\times 10^{-5}$. The predictions of ${\cal B}(Λ_b\to J/ψΛ)$ and ${\cal B}(Ξ_b^-\to J/ψΞ^-)$ clearly enable us to test the theoretical models, such as the QCD factorization approach in the $b$-baryon decays.

hep-ph↗

arXiv2015

A new measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully-constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9$\times$10$^5$ GW$_{\rm th}$-ton-days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six $^{241}$Am-$^{13}$C radioactive calibration sources reduced the background by a factor of two for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of $\sin^{2}2θ_{13}$ and $|Δm^2_{ee}|$ were halved as a result of these improvements. Analysis of the relative antineutrino rates and energy spectra between detectors gave $\sin^{2}2θ_{13} = 0.084\pm0.005$ and $|Δm^{2}_{ee}|= (2.42\pm0.11) \times 10^{-3}$ eV$^2$ in the three-neutrino framework.

hep-ex↗

arXiv2014

Search for a Light Sterile Neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9~GW$_{\rm th}$ nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512~m and 561~m) and one far (1579~m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the $10^{\rm -3}~{\rm eV}^{2} < |Δm_{41}^{2}| < 0.3~{\rm eV}^{2}$ range. The relative spectral distortion due to electron antineutrino disappearance was found to be consistent with that of the three-flavor oscillation model. The derived limits on $\sin^22θ_{14}$ cover the $10^{-3}~{\rm eV}^{2} \lesssim |Δm^{2}_{41}| \lesssim 0.1~{\rm eV}^{2}$ region, which was largely unexplored.

hep-ex↗

arXiv2014

Independent Measurement of Theta13 via Neutron Capture on Hydrogen at Daya Bay

A new measurement of the $θ_{13}$ mixing angle has been obtained at the Daya Bay Reactor Neutrino Experiment via the detection of inverse beta decays tagged by neutron capture on hydrogen. The antineutrino events for hydrogen capture are distinct from those for gadolinium capture with largely different systematic uncertainties, allowing a determination independent of the gadolinium-capture result and an improvement on the precision of $θ_{13}$ measurement. With a 217-day antineutrino data set obtained with six antineutrino detectors and from six 2.9 GW$_{th}$ reactors, the rate deficit observed at the far hall is interpreted as $\sin^22θ_{13}=0.083\pm0.018$ in the three-flavor oscillation model. When combined with the gadolinium-capture result from Daya Bay, we obtain $\sin^22θ_{13}=0.089\pm0.008$ as the final result for the six-antineutrino-detector configuration of the Daya Bay experiment.

hep-ex↗