13990506
Dynamics study of Z+(4430) and X(3872) in molecular picture
In this talk, we review our recent work about the dynamical studies of Z+(4430) and X(3872). Z+(4430) can not be explained as a D1′D* or D1D* molecular state only considering one pion exchange potential without the cutoff, which needs to be confirmed by introducing sigma exchange potential and adding the cutoff in the effective potential. One also excludes the possibility of X(3872) as a DD* molecular state by one pion and one sigma exchanges with the cutoff. Fortunately there exists an S‐wave BB* bound state with JPC = 1++. we suggest future experiment to search this state.
28437592
A possible global group structure for exotic states
Based on the fact that the long expected pentaquark which possesses the exotic quantum numbers of $$B=1$$B=1 and $$S=1$$S=1 was not experimentally found, although exotic states of $$XYZ$$XYZ have been observed recently, we conjecture that the heavy flavors may play an important role in stabilizing the hadronic structures beyond the traditional $$q\bar{q}$$qq¯ and $$qqq$$qqq composites.
31555802
Mixing of Pentaquark and Molecular States
There are experimental evidences for the existence of narrow states Θ+ and Θc with the same quantum numbers of uudds̄ and uuddc̄ pentaquarks and also NK(∗) and ND(∗) molecular states. Their masses deviate from many theoretical estimates of the pure pentaquark and molecular states. In this work we study the possibility that the observed Θ+ and Θc are mixtures of pure pentaquark and molecular states. The mixing parameters are in general related to non-perturbative QCD which are not calculable at present. We determine them by fitting data from known states and then generalize the mechanism to Θb to predict its mass and width. The mixing mechanism can also naturally explain the narrow width for Θ+ and Θc through destructive interferences, even if the pure pentaquark and molecular states have much larger decay widths. We also briefly discuss the properties of the partner eigenstates of Θ+ and Θc and the possibility of experimentally observe them. Moreover, probable consequences of multi-state mixing are also addressed.
51398146
Some properties of the newly observed X(1835) state at BES
Recently the BES collaboration has announced the observation of a resonant state in the π+π-η’ spectrum in J/ψ→γπ+π-η’ decay. Fitting the data with a 0-+ state, the mass is determined to be 1833.7 MeV with 7.7σ statistic significance. This state is consistent with the one extracted from previously reported pp̄ threshold enhancement data in J/ψ→γpp̄. We study the properties of this state using QCD anomaly and QCD sum rules, assuming X(1835) to be a pseudoscalar, and we show that it is consistent with the data. We find that this state has a sizeable matrix element $\langle0|G\widetilde{G}|G_{\text{p}}\rangle$, leading to branching ratios of (2.61–7.37)×10-3 and (2.21–10.61)×10-2 for J/ψ→γGp and for Gp→π+π-η′, respectively. Combining the calculated branching ratio of J/ψ→γGp and data on threshold enhancement in J/ψ→γpp̄, we determine the coupling for the Gp–p–p̄ interaction. We finally study the branching ratios of the other J/ψ→γ+three mesons decay modes. We find that J/ψ→γGp→γ(π+π-η,KKπ0) can provide useful tests for the mechanism proposed.
119249008
Does the enhancement observed in $\gamma\gamma\to D\bar{D}$ contain two P-wave higher charmonia?
We solve a new puzzle raised by the observation of an enhancement structure Z(3930) in $\gamma\gamma\to D\bar{D}$. If categorizing Z(3930) as χc2(2P), as suggested by Belle and BaBar, we must explain why χc0(2P) dominantly decaying into $D\bar{D}$ is missing in the $D\bar{D}$ invariant mass spectrum. In this work, we propose that the Z(3930) enhancement structure may contain two P-wave higher charmonia χc0(2P) and χc2(2P). We show that this assumption is supported by our analysis of the $D\bar{D}$ invariant mass spectrum and cosθ∗ distribution of $\gamma\gamma\to D\bar{D}$. This observation would not only provide valuable information of two P-wave higher charmonia χc0(2P) and χc2(2P), but also serve as the crucial test of our novel proposal to the observed enhancement structure Z(3930), especially at the forthcoming BelleII and the approved SuperB.
119155043
Effects of hadronic loops on the direct CP violation of $B_c$
It is well-known that the final state interaction plays an important role in the decays of B meson. The contribution of the final state interaction, which is supposed to be long-distance effects, to the concerned processes can interfere with that of the short-distance effects produced via the tree and/or loop diagrams at quark-gluon level. The interference may provide a source for the direct CP violation A{sub CP} in the process B{sub c}{sup +}{yields}D{sup 0}{pi}{sup +}. We find that a typical value of A{sub CP} when the final state interaction effect is taken into account can be about -22% which is different from that without the final state interaction effect. Therefore, when we extract information on CP violation from the data which will be available at the Large Hadron Collider beauty experiment (LHCb) and the new experiments in B factories, the contribution from the final state interaction must be included. This study may be crucial for searching new physics in the future.
119208539
1-jettiness DIS event shape: NNLL+NLO results
We present results for the complete NNLL+NLO (~ \alpha_s) 1-jettiness (\tau_1) event shape distribution for single jet (J) production in electron-nucleus (N_A) collisions e^- + N_A \to e^- + J + X, in the deep inelastic scattering (DIS) region where the hard scale is set by the jet transverse momentum P_{J_T}. These results cover the entire \tau_1-spectrum including the resummation (\tau_1<<P_{J_T}) and fixed-order (\tau_1~ P_{J_T}) perturbative QCD regions. They incorporate non-perturbative soft radiation effects, the anti-k_T jet algorithm in the fixed-order calculation, and a smooth matching between the resummation and fixed-order perturbative QCD regions. The matching smoothly connects the spectrum in the resummation region, which can be computed without reference to an external jet algorithm, and the fixed-order region where an explicit jet algorithm must be specified. Our code, used for generating the numerical results, is flexible enough to incorporate different jet algorithms for the fixed-order calculation. We also perform a jet shape analysis, defined within the 1-jettiness framework, which allows one to control the amount of radiation included in the definition of the final state jet. This formalism can allow for detailed studies of jet energy-loss mechanisms and nuclear medium effects. The analysis presented here can be used for precision studies of QCD and as a probe of nuclear dynamics using data collected at HERA and in proposed future electron-ion colliders such as the EIC and the LHeC.
24721947
Development of the Central Task Processing Unit for space-borne Gamma-Ray Burst polarimeter, POLAR
POLAR, a joint European-Chinese experiment, is a novel compact space-borne Compton polarimeter conceived and optimized for detection of the prompt emission of Gamma-Ray Bursts (GRB) and precise measurements of polarization in the hard X-ray energy range 50-500 keV. The complete instrument consists of two parts: internal one, placed inside spacelab and the detector itself, placed outside spacelab, called respectively IBOX and OBOX. The OBOX constitutes of 25 frontend electronic modules (FEE), high voltage and low voltage power supplies and the Central Task Processing Unit. The main functions of Central Task Processing Unit system are defined as follows: communication and transfer of data to IBOX, communication with all frontends, analysis of trigger signals and generation of global trigger signals, data acquisition, synchronizing of all frontends and control of power supplies. The functional requirements are fulfilled by three individual FPGA chips named respectively to their functions: Concentrator, Trigger and CPU. This article presents description of the Central Task Processing Unit hardware design and brief introduction to main components of the firmware developed for this device. Ongoing integration activities of the device with the complete POLAR instrument proved that all basic functions are working correctly. The qualification model of the instrument has been constructed and currently undergoes verification and validation tests in view of planned flight onboard the Chinese spacelab TG-2 scheduled for 2015.
18223996
Beauty is attractive: Moduli trapping at enhanced symmetry points
We study quantum effects on moduli dynamics arising from the production of particles which are light at points of enhanced symmetry in moduli space. The resulting forces trap the moduli at these points. Moduli trapping occurs in time-dependent quantum field theory, as well as in systems of moving D-branes, where it leads the branes to combine into stacks. Trapping also occurs in the presence of gravity, though the range over which the moduli can roll is limited by Hubble friction. We observe that a scalar field trapped on a steep potential can induce a stage of acceleration of the universe, which we call trapped inflation. Moduli trapping ameliorates the cosmological moduli problem and may affect vacuum selection. In particular, rolling moduli are most powerfully attracted to the points of greatest symmetry. Given suitable assumptions about the dynamics of the very early universe, this effect might help to explain why among the plethora of possible vacuum states of string theory, we appear to live in one with a large number of (spontaneously broken) symmetries.
17128857
Are CSO host-galaxies undergoing merging?
The galaxy-type CSO (compact symmetric objects) rate from an intermediate large sample PR+CJ1 is found to be consistent with the Sb-Sb merger rate of 4.6% in redshift z 1, yet no deep VLBI sample in z>1 is available now.
102486763
High precision predictions for exclusive V H production at the LHC
A bstractWe present a resummation-improved prediction for pp → V H + 0 jets at the Large Hadron Collider. We focus on highly-boosted final states in the presence of jet veto to suppress the $ t\overline{t} $ background. In this case, conventional fixed-order calculations are plagued by the existence of large Sudakov logarithms $ \alpha_s^n{\log^m}\left( {{{{p_T^{\mathrm{veto}}}} \left/ {Q} \right.}} \right) $ for Q ~ mV + mH which lead to unreliable predictions as well as large theoretical uncertainties, and thus limit the accuracy when comparing experimental measurements to the Standard Model. In this work, we show that the resummation of Sudakov logarithms beyond the next-to-next-to-leading-log accuracy, combined with the next-to-next-to-leading order calculation, reduces the scale uncertainty and stabilizes the perturbative expansion in the region where the vector bosons carry large transverse momentum. Our result improves the precision with which Higgs properties can be determined from LHC measurements using boosted Higgs techniques.