Searcharxiv⌕ Search

arXiv subjects

Long-Fei Gan

Publications and source records attributed to Long-Fei Gan.

7 recordsLinked to original sources
arXiv2015

$D_{sJ}(2860)$ From The Semileptonic Decays Of $B_s$ Mesons

In the framework of heavy quark effective theory, the leading order Isgur-Wise form factors relevant to semileptonic decays of the ground state $\bar{b}s$ meson $B_{s}$ into orbitally excited $D$-wave $\bar{c}s$ mesons, including the newly observed narrow $D^{*}_{s1}(2860)$ and $D^{*}_{s3}(2860)$ states by the LHCb Collaboration, are calculated with the QCD sum rule method. With these universal form factors, the decay rates and branching ratios are estimated. We find that the decay widths are $Γ(B_s\rightarrow D^{*}_{s1}\ell\barν) =1.25^{+0.80}_{-0.60}\times10^{-19} \mbox{GeV}$, $Γ(B_s\rightarrow D^{'}_{s2}\ell\barν) =1.49^{+0.97}_{-0.73}\times10^{-19} \mbox{GeV}$, $Γ(B_s\rightarrow D_{s2}\ell\barν) =4.48^{+1.05}_{-0.94}\times10^{-17} \mbox{GeV}$, and $Γ(B_s\rightarrow D^{*}_{s3}\ell\barν) = 1.52^{+0.35}_{-0.31}\times10^{-16} \mbox{GeV}$. The corresponding branching ratios are $\mathcal {B}(B_s\rightarrow D^{*}_{s1}\ell\barν) =2.85^{+1.82}_{-1.36}\times 10^{-7}$, $\mathcal {B}(B_s\rightarrow D^{'}_{s2}\ell\barν) =3.40^{+2.21}_{-1.66}\times 10^{-7}$, $\mathcal {B}(B_{s}\rightarrow D_{s2}\ell\barν) =1.02^{+0.24}_{-0.21}\times 10^{-4}$, and $\mathcal {B}(B_s\rightarrow D^{*}_{s3}\ell\barν) = 3.46^{+0.80}_{-0.70}\times 10^{-4}$. The decay widths and branching ratios of corresponding $B^{*}_{s}$ semileptonic processes are also predicted.

hep-ph↗
arXiv2012

Improved Light-cone QCD Sum Rule Analysis Of The Rare Decays $Λ_b\rightarrowΛγ$ And $Λ_b\rightarrowΛl^+l^-$

We present a systematic light-cone QCD sum rule study of the exclusive rare radiative decay $Λ_b\rightarrowΛγ$ and rare semileptonic decay $Λ_b\rightarrowΛl^+l^-$ within the framework of the standard model. Although some LCSR studies on these rare processes can be found in different literatures, it is necessary to reanalyze them systematically for the reason that either the baryonic distribution amplitudes are improved or different interpolating currents for the $Λ_b$ baryon may lead to quite different results. In addition, the rare process $Λ_b\rightarrowΛγ$ has not yet been analyzed by LCSR with the Ioffe-type current. Taking all these reasons into account, we perform LCSR calculations of both the processes with two types of interpolating currents. Our calculations show that the choice of the interpolating current for the $Λ_b$ baryon can affect the predictions significantly, especially for the rare radiative decay process.

hep-ph↗
arXiv2012

Search for $Z^{+}_{s1}$ and $Z^{+}_{s2}$ strangeonium-like structures

Theoretically, it has been presumed from an effective Lagrangian calculation that there could exist two charged strangeonium-like molecular states $Z^{+}_{s1}$ and $Z^{+}_{s2}$, with $K\bar{K}^{*}$ and $K^{*}\bar{K}^{*}$ configurations respectively. In the framework of QCD sum rules, we predict that masses of $Z^{+}_{s1}$ ($K\bar{K}^{*}$) and $Z^{+}_{s2}$ ($K^{*}\bar{K}^{*}$) are $1.85\pm0.14 GeV$ and $2.02\pm0.15 GeV$ respectively, which are both above their respective two meson thresholds. We suggest to put in practice the search for these two charged strangeonium-like structures in future experiments.

hep-ph↗
arXiv2011

Semileptonic Decays of $B^{**}_{s}$ mesons into $D_{s1}$ and $D^{*}_{s2}$ in HQET

In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonic decays of the orbitally $P$-wave excited $B_{s}$ meson states $B^{**}_{s}$, including the newly found narrow $B_{s1}(5830)$ and $B^{*}_{s2}(5840)$ states, into the ($D_{s1}(2536)$, $D^{*}_{s2}(2573)$) doublet are calculated from QCD sum rules. With these universal form factors, the decay rates and branching ratios are also estimated.

hep-ph↗
arXiv2010

QCD Sum Rule Analysis of Semileptonic $B_{s1}$, $B^{*}_{s2}$, $B^{*}_{s0}$, and $B'_{s1}$ Decays in HQET

We present an analysis of semileptonic decays of orbitally, $P$-wave excited $B_{s}$ meson states $B^{**}_{s}$, including the newly found narrow $B_{s1}(5830)$ and $B^{*}_{s2}(5840)$ states, into low lying $D_{s}$ mesons ($D_{s}(1968)$, $D^{*}_{s}(2112)$, $D_{sJ}(2317)$, $D_{sJ}(2460)$) within the framework of heavy quark effective theory. The relevant universal form factors are estimated using QCD sum rules at the leading-order of the heavy quark expansion. The decay widths are predicted and the branching ratios are estimated.

hep-ph↗
arXiv2009

Semileptonic $B$ Meson Decays Into A Highly Excited Charmed Meson Doublet

We study the heavy quark effective theory prediction for semileptonic $B$ decays into an orbital excited $F$-wave charmed doublet, the ($2^{+}$, $3^{+}$) states ($D^{*'}_{2}$, $D_{3}$), at the leading order of heavy quark expansion. The corresponding universal form factor is estimated by using the QCD sum rule method. The decay rates we predict are $Γ_{B\to D^{*'}_{2}\ell\overlineν}=1.85\times10^{-19} {GeV}$ and $Γ_{B\to D_{3}\ell\overlineν}=1.78\times10^{-19} {GeV}$. The branching ratios are $\mathcal {B}(B\to D_{2}^{*'}\ell\overlineν)=4.6\times10^{-7}$ and $\mathcal {B}(B\to D_{3}\ell\overlineν)=4.4\times10^{-7}$, respectively.

hep-ph↗
arXiv2009

Semileptonic Decays of B Meson Transition Into D-wave Charmed Meson Doublets

We use QCD sum rules to estimate the leading-order universal form factors describing the semileptonic B decay into orbital excited $D$-wave charmed doublets, including the ($1^{-}$, $2^{-}$) states ($D_{1}^{*}$, $D'_{2}$) and the ($2^{-}$, $3^{-}$) states ($D_{2}$, $D_{3}^{*}$). The decay rates we predict are $Γ_{B\to D^{*}_{1}\ell\overlineν}=Γ_{B\to D'_{2}\ell\overlineν}=2.4\times10^{-18} {GeV}$, $Γ_{B\to D_{2}\ell\overlineν}=6.2\times10^{-17} {GeV}$, and $Γ_{B\to D_{3}^{*}\ell\overlineν}=8.6\times10^{-17} {GeV}$. The branching ratios are $\mathcal {B}(B\to D^{*}_{1}\ell\overlineν)=\mathcal {B}(B\to D'_{2}\ell\overlineν)=6.0\times10^{-6}$, $\mathcal {B}(B\to D_{2}\ell\overlineν)=1.5\times10^{-4}$, and $\mathcal {B}(B\to D_{3}^{*}\ell\overlineν)=2.1\times10^{-4}$, respectively.

hep-ph↗