Publications (210)540.54 Total impact
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ABSTRACT: The QCD multipole expansion (QCDME) is based on the quantum field theory, so should be more reliable. However, on another aspect, it refers to the nonperturbative QCD , so that has a certain application range. Even though it successfully explains the data of transition among members of the $\Upsilon$ ($\psi$) family, as Eichten indicates, beyond the production threshold of mediate states it fails to meet data by several orders. In this work, by studying a simple decay mode $D^*\to D+\pi^0$, where a pion may be emitted before $D^*$ transiting into $D$, we analyze the contribution of QCD multipole expansion. Whereas as the $D\pi$ portal is open, the dominant contribution is an OZI allowed process where a light quarkpair is excited out from vacuum and its contribution can be evaluated by the $^3P_0$ model. Since the direct pion emission is a process which is OZI suppressed and violates the isospin conservation, its contribution must be much smaller than the dominant one. By a careful calculation, we may quantitatively estimate how small the QCDME contribution should be and offer a quantitative interpretation for Eichten's statement.  [Show abstract] [Hide abstract]
ABSTRACT: The discovery of the new resonances $P_c(4380)$ and $P_c(4450)$ indeed opens a new page for hadron physics. They are identified as the longexpected pentaquarks. Now the GellMann's quark model is complete. On the other aspect, the light multiquark exotic states are not stable, so cannot exist individually but mix with the regular structures with the same quantum numbers. With heavy flavors which play an important role to stabilize the systems, the multiquark states are able to exist. The allegation is not only true for the exotic mesons which have already been experimentally observed and named as $X$, $Y$, $Z$ particles, but also for the baryons which have $Q\bar Q qqq$ structures. Further experimental and theoretical research should be pursued in the future.Physical Review Letters 07/2015; 115(13). DOI:10.1103/PhysRevLett.115.132002 · 7.51 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Investigating the CKM matrix in different parametrization schemes, it is noticed that those schemes can be divided into a few groups where the sine values of the CP phase for each group are approximately equal. Using those relations, several approximate equalities among the elements of CKM matrix are established. Assuming them to be exact, there are infinite numbers of solutions and by choosing special values for the free parameters in those solutions, several textures presented in literature are obtained. The case can also be generalized to the PMNS matrix for the lepton sector. In parallel, several mixing textures are also derived by using presumed symmetries, amazingly, some of their forms are the same as what we obtained, but not all. It hints existence of a hidden symmetry which is broken in the practical world. The nature makes its own selection on the underlying symmetry and the way to break it, while we just guess what it is. 
Dataset: 2015(2)CPC ??

Dataset: 2015(2)CPC 苏健
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ABSTRACT: The approximately symmetric form of the PMNS matrix suggests that there could exist a hidden symmetry which makes the PMNS matrix different from the CKM matrix for quarks. In literature, all the proposed fully symmetric textures exhibit an explicit $\mu\tau$ symmetry in addition to other symmetries which may be different for various textures. Observing obvious deviations of the practical PMNS matrix elements from those in the symmetric textures, there must be a mechanism to distort the symmetry. It might be due to existence of light sterile neutrinos. In this work, we study the case of the Tribimaximal texture and propose that its apparent symmetry disappears due to existence of a sterile neutrino. We observe that introducing just one sterile neutrino is still not sufficient to recover the data, thus a slight $\mu\tau$ symmetry breaking is also needed. By considering those factors, we obtain the PMNS matrix elements which are consistent with data within the experimental tolerance.Modern Physics Letters A 02/2015; 30(27). DOI:10.1142/S0217732315501369 · 1.20 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Observing the CKM matrix elements written in different parametrization schemes, one can notice obvious relations among the sinevalues of the CP phases in those schemes. Using the relations, we establish a few parametrizationindependent equations, by which the matrix elements of the CKM matrix can be completely fixed up to a universal parameter. If it is true, we expect that there should exist a hidden symmetry in the nature which determines the relations. Moreover, it requires a universal parameter, naturally it would be the famous Jarlskog invariant which is also parametrization independent. Thus the four parameters (three mixing angles and one CP phase) of the CKM matrix are not free, but determined by the symmetry and the universal parameter. As we generalize the rules to the PMNS matrix for neutrino mixing, the CP phase of the lepton sector is predicted to be within a range of $0\sim 59^\circ$ centered at $39^\circ$ (in the P$_a$ parametrization) which will be tested in the future experiments.Communications in Theoretical Physics 11/2014; 64(5). DOI:10.1088/02536102/64/5/519 · 0.89 Impact Factor 
Article: Study on radiative decays of $D^*_{sJ}(2860)$ and $D^*_{s1}(2710)$ into $D_s$ by means of LFQM
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ABSTRACT: The observed resonance peak around 2.86 GeV has been carefully reexamined by the LHCb collaboration and it is found that under the peak there reside two states $D^*_{s1}(2860)$ and $D^*_{s3}(2860)$ which are considered as $1^3D_1(c\bar s)$ and $1^3D_3(c\bar s)$ with slightly different masses and total widths. Thus, the earlier assumption that the resonance $D^*_{s1}(2710)$ was a $1D$ state should not be right. We suggest to measure the partial widths of radiative decays of $D^*_{sJ}(2860)$ and $D^*_{s1}(2710)$ to confirm their quantum numbers. We would consider $D^*_{s1}(2710)$ as $2^3S_1$ or a pure $1^3D_1$ state, or their mixture and respectively calculate the corresponding branching ratios as well as those of $D^*_{sJ}(2860)$. The future precise measurement would provide us information to help identifying the structures of those resonances .European Physical Journal C 11/2014; 75(1). DOI:10.1140/epjc/s1005201532645 · 5.08 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: In this work, we use the BornOppenheimer approximation where the potential between atoms can be approximated as a function of distance between the two nuclei to study the fourquark bound states. By the approximation, Heitler and London calculated the spectrum of hydrogen molecule which includes two protons (heavy) and two electrons (light). Generally, the observed exotic mesons $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$ and $Z_c(4025)$($Z_c(4020)$) may be molecular states of two physical mesons and/or in diquarkantidiquark structures. In analog to the HeitlerLondon method for calculating the mass of hydrogen molecule, we investigate whether there exist energy minima for these two structures. By contrary to the hydrogen molecule case where only the spintriplet possesses an energy minimum, there exist minima for both of them. It implies that both molecule and tetraquark states can be stable objects. But since they have the same quantum numbers, the two states may mix to result in physical states. A consequence would be that one may expect to experimentally observe partner exotic states coexisting with $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$ and $Z_c(4025)$($Z_c(4020)$).Chinese Physics C 09/2014; 39(8). DOI:10.1088/16741137/39/8/083103 · 1.31 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Based on the fact that the long expected pentaquark which possesses exotic quantum numbers of $B=1$ and $S=1$ was not experimentally found, but exotic states of $XYZ$ have been observed recently, we conjecture that the heavy flavors may play an important role for stabilizing the hadronic structures beyond the traditional $q\bar q$ and $qqq$ composites.European Physical Journal C 09/2014; 74(12). DOI:10.1140/epjc/s1005201431983 · 5.08 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: It is suggested that there is an underlying symmetry which relates the quark and lepton sectors. Namely, among the mixing matrix elements of CKM for quarks and PMNS for leptons there exist complementarity relations at a high energy scale (such as the seesaw or even the GUT scales). Assuming that the relations would remain during the matrix elements running down to the EW scale. Observable breaking of the rational relation is attributed to existence of sterile neutrinos which mix with the active neutrino to result in the observable PMNS matrix. We show that involvement of a sterile in the (3+1) model, induces that $U_{e4}^2= 0.040$, $U_{\mu4}^2= 0.009$ and $\sin^2 2\alpha=0.067$. We also find a new selfcomplementarity $\vartheta_{12}+\vartheta_{23}+\vartheta_{13}+\alpha\approx90^\circ$. The numbers are generally consistent with those obtained by fitting recent measurements, especially in this scenario, the existence of a sterile neutrino does not upset the LEP data i.e. the number of neutrino types is very close to 3.Physical Review D 08/2014; 90(5). DOI:10.1103/PhysRevD.90.053009 · 4.64 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The China Dark Matter Experiment (CDEX) is located at the China Jinping underground laboratory (CJPL) and aims to directly detect the WIMP flux with high sensitivity in the low mass region. Here we present a study of the predicted photon and electron backgrounds including the background contribution of the structure materials of the germanium detector, the passive shielding materials, and the intrinsic radioactivity of the liquid argon that serves as an antiCompton active shielding detector. A detailed geometry is modeled and the background contribution has been simulated based on the measured radioactivities of all possible components within the GEANT4 program. Then the photon and electron background level in the energy region of interest (<10^2 events kg1 day1 keV1 (cpkkd)) is predicted based on Monte Carlo simulations. The simulated result is consistent with the design goal of CDEX10 experiment, 0.1 cpkkd, which shows that the active and passive shield design of CDEX10 is effective and feasible.Chinese Physics C 02/2014; 39(3). DOI:10.1088/16741137/39/3/036001 · 1.31 Impact Factor 
Article: Search for supersymmetric mesinos near production threshold in terms of superflavor symmetry
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ABSTRACT: The supersymmetry (SUSY) may be one of the most favorable extensions of the standard model (SM), however, so far at LHC no evidence of the SUSY particles were observed. An obvious question is whether they have already emerged, but escaped from our detection, or do not exist at all. We propose that the future ILC may provide sufficient energy to produce SUSY particles if they are not too heavy in the low background environment. The superflavor symmetry associates baryons with mesons as long as both of them containing a heavy constituent and a light one. In this work, we estimate the production rate of SUSY baryons near their production threshold in terms of the $B\bar B$ production data. Our analysis indicates that if the SUSY baryons with masses below $\sqrt s/2$ ($\sqrt s$ is the ILC energy) exist, they could be observed at future ILC.Chinese Physics C 01/2014; 39(8). DOI:10.1088/16741137/39/8/083102 · 1.31 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The LHCb Collaboration has systematically measured the rates of Bc→J /ψK, Bc→J/ψDs, Bc→J /ψDs*, and Bc→ψ(2S)π. The new data enable us to study relevant theoretical models and further determine the model parameters. In this work, we calculate the form factors for the transitions Bc→J /ψ and Bc→ψ(2S) numerically and then determine the partial widths of the semileptonic and nonleptonic decays. The theoretical predictions on the ratios of Γ(Bc→J/ψK)/Γ(Bc→J/ψπ), Γ(Bc→J/ψDs)/Γ(Bc→J/ψπ), and Γ(Bc→J/ψDs*)/Γ(Bc→J/ψπ) are consistent with data within only 1σ. Especially, for calculating Γ(Bc→ψ(2S)X) the modified harmonic oscillator wave function which we developed in early works is employed, and the results indicate that the modified harmonic oscillator wave function works well.Physical Review D 12/2013; 89(1). DOI:10.1103/PhysRevD.89.017501 · 4.64 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: In contrast with $B^0\bar B^0$, $B_s\bar B_s$ mixing where the standard model (SM) contributions overwhelm that of new physics beyond standard model (BSM), a measured relatively large $D^0\bar D^0$ mixing where the SM contribution is negligible, definitely implies the existence of new physics BSM. It is natural to consider that the rare decays of D meson might be more sensitive to new physics, and the rare decay $D^0\to \mu^+\mu^$ could be an ideal area to search for new physics because it is a flavor changing process. In this work we look for a trace of new physics BSM in the leptonic decays of $D^0$, concretely we discuss the contributions of unparticle or an extra gauge boson $Z'$ while imposing the constraints set by fitting the $D^0\bar D^0$ mixing data. We find that the longdistance SM effects for $D^0\to l\bar l$ still exceed those contributions of the BSM under consideration, but for a doubleflavor changing process such as $D^0\to \mu^{\pm}e^{\mp}$, the new physics contribution would be significant. 
Article: Is Z c (3900) a molecular state?
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ABSTRACT: Assuming the newly observed Z c (3900) to be a molecular state of \(D\bar{D}^{*}(D^{*} \bar{D})\), we calculate the partial widths of Z c (3900)→J/ψ+π; ψ′+π; η c +ρ and \(D\bar{D}^{*}\) within the lightfront model (LFM). Z c (3900)→J/ψ+π is the channel by which Z c (3900) was observed, our calculation indicates that it is indeed one of the dominant modes whose width can be in the range of a few MeV depending on the model parameters. Similar to Z b and \(Z_{b}'\), Voloshin suggested that there should be a resonance \(Z_{c}'\) at 4030 MeV, which can be a molecular state of \(D^{*}\bar{D}^{*}\). Then we go on calculating its decay rates to all the aforementioned final states and the \(D^{*}\bar{D}^{*}\) as well. It is found that if Z c (3900) is a molecular state of \({1\over\sqrt{2}}(D\bar{D}^{*}+D^{*}\bar{D})\), the partial width of \(Z_{c}(3900)\to D\bar{D}^{*}\) is rather small, but the rate of Z c (3900)→ψ(2s)π is even larger than Z c (3900)→J/ψπ. The implications are discussed and it is indicated that with the luminosity of BES and BELLE, the experiments may finally determine if Z c (3900) is a molecular state or a tetraquark.European Physical Journal C 10/2013; 73(10). DOI:10.1140/epjc/s1005201325610 · 5.08 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The new observation of CDMS II favors low mass WIMPs. Taking the CDMS II new results as input and following the literature we consider a SM singlet: the darkon as the dark matter candidate, which can be either scalar, fermion or vector. It is found that the simplest scenario of DM+SM conflicts with the stringent constraint set by the LHC data. New physics beyond the SM is needed as many authors suggested. In this work, we discuss an extended standard model $SU_L(2)\otimes U_Y(1)\otimes U(1)'$ where $U(1)'$ only couples to the darkon. The new gauge symmetry is broken into $U_{em}(1)$ and two neutral bosons $Z^0$ and $Z'$ which are mixtures of $W^3_{\mu},\; B_{\mu}\; X_{\mu}$ are resulted in, where $Z^0$ is very close to the $Z$ boson of the standard model. Following the literature and based on the CDMS data, we make a complete analysis to testify the validity of the model. The cross section of the elastic scattering between darkon and nucleon is calculated, and the DM relic density is evaluated in the extended scenario as well. It is found that considering the constraints from both cosmology and collider experiments, only if $Z'$ is lighter than $Z^0$, one can reconcile all the presently available data.Physical Review D 09/2013; 89(3). DOI:10.1103/PhysRevD.89.035006 · 4.64 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We calculate the forward backward asymmetry of the toppair production at TEVATRON up to next to leading order (NLO) in the little Higgs model (LHM). We find that the contribution of $Z_H$ can be large enough to make up the gap between standard model (SM) prediction and data. With the database of $7.65\pm0.20\pm0.36$ pb, therefore, the parameter space for flavorchanging coupling of $Z_H$ is constrained. Thus this model can result in the required asymmetry while the total cross section of toppair production remaining consistent with data.Chinese Physics C 09/2013; 38(11). DOI:10.1088/16741137/38/11/113102 · 1.31 Impact Factor  Chinese Physics Letters 09/2013; 30(9):099901. DOI:10.1088/0256307X/30/9/099901 · 0.95 Impact Factor

Article: Is $Z_c(3900)$ a molecular state
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ABSTRACT: Assuming the newly observed $Z_c(3900)$ to be a molecular state of $D\bar D^*(D^{*} \bar D)$, we calculate the partial widths of $Z_c(3900)\to J/\psi+\pi;\; \psi'+\pi;\; \eta_c+\rho$ and $D\bar D^*$ within the light front model (LFM). $Z_c(3900)\to J/\psi+\pi$ is the channel by which $Z_c(3900)$ was observed, our calculation indicates that it is indeed one of the dominant modes whose width can be in the range of a few MeV depending on the model parameters. Similar to $Z_b$ and $Z_b'$, Voloshin suggested that there should be a resonance $Z_c'$ at 4030 MeV which can be a molecular state of $D^*\bar D^*$. Then we go on calculating its decay rates to all the aforementioned final states and as well the $D^*\bar D^*$. It is found that if $Z_c(3900)$ is a molecular state of ${1\over\sqrt 2}(D\bar D^*+D^*\bar D)$, the partial width of $Z_c(3900)\to D\bar D^*$ is rather small, but the rate of $Z_c(3900)\to\psi(2s)\pi$ is even larger than $Z_c(3900)\to J/\psi\pi$. The implications are discussed and it is indicated that with the luminosity of BES and BELLE, the experiments may finally determine if $Z_c(3900)$ is a molecular state or a tetraquark.
Publication Stats
2k  Citations  
540.54  Total Impact Points  
Top Journals
Institutions

19942015

Nankai University
 Department of Physics
T’ienchingshih, Tianjin Shi, China


2007

Peking University
 Department of Physics
Peping, Beijing, China


2005

National Taiwan University
 Department of Physics
T’aipei, Taipei, Taiwan


2004

Chinese Academy of Sciences
 Institute of Theoretical Physics
Peping, Beijing, China


2002

University of Adelaide
 Special Research Centre for the Subatomic Structure of Matter
Tarndarnya, South Australia, Australia


19901997

Academia Sinica
T’aipei, Taipei, Taiwan
