Publications Others

Latest additions:
2015-10-13
20:54
Search for supersymmetric mesinos near production threshold in terms of superflavor symmetrySupported by National Natural Science Foundation of China (11075079, 11135009, 11005061) / Jia, Lian-Bao ; Guo, Xing-Dao ; Jin, Hong-Ying ; Zhao, Ming-Gang ; et al [arXiv:1409.5939v3] Supersymmetry (SUSY) may be one of the most favored extensions of the Standard Model (SM), but so far at the LHC no evidence of SUSY particles has been observed. An obvious question is whether they have already emerged but escaped our detection, or whether they do not exist at all. We propose that the future ILC may provide sufficient energy and luminosity to produce SUSY particles as long as they are not too heavy. Superflavor symmetry associates production rates of SUSY mesinos with those of regular mesons, because both contain a heavy constituent and a light one. In this work, we estimate the production rate of SUSY mesinos near their production threshold and compare it with BB production. Our analysis indicates that if SUSY mesinos with masses below √s/2 (√s is the ILC energy) exist, they could be observed at the future ILC or even the proposed CEPC in China. 10.1088/1674-1137/39/8/083102
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
Study of the structures of four-quark states in terms of the Born-Oppenheimer approximationSupported by National Natural Science Foundation of China (11375128) / Liu, Xue-Wen ; Ke, Hong-Wei ; Ding, Yi-Bing ; Li, Xue-Qian [arXiv:1401.6566arXiv:1409.5939] In this work, we use the Born-Oppenheimer approximation, where the potential between atoms can be approximated as a function of distance between the two nuclei, to study the four-quark bound states. By this approximation, Heitler and London calculated the spectrum of the hydrogen molecule, which includes two protons (heavy) and two electrons (light). Generally, the observed exotic mesons Zb(10610), Zb(10650), Zc(3900) and Zc(4020) (Zc(4025)) may be molecular states made of two physical mesons and/or diquark-anti-diquark structures. Analogous to the Heitler-London method for calculating the mass of the hydrogen molecule, we investigate whether there exist energy minima for these two structures. Contrary to the hydrogen molecule case where only the spin-triplet possesses an energy minimum, there exist minima for both of these states. This implies that both molecule and tetraquark states can be stable objects. Since they have the same quantum numbers, however, the two states may mix to result in the physical states. A consequence would be that partner exotic states co-existing with Zb (10610), Zb (10650), Zc (3900) and Zc (4020) (Zc (4025)) are predicted and should be experimentally observed. 10.1088/1674-1137/39/8/083103
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
I=1/2 low-lying mesons in lattice QCDSupported by National Natural Science Foundation of China (11175124) and National Magnetic Confinement Fusion Program of China (2013GB109000) / Fu, Zi-Wen [arXiv:1412.1218arXiv:1412.1218] Using a conventional constituent-quark model, I = 1/2 scalar κ, vector K*(892), and axial vector K1 mesons are studied in the asqtad-improved staggered fermion with wall-source and point-sink interpolators. The mass ratio of mκ/mK*(892) is numerically confirmed to apparently vary with quark mass, and the experimental ordering mK*(892) >mκ holds elegantly when the light u/d quark masses are sufficiently small, while the valence strange quark mass is fixed to its physical value. We also get reasonable signals for the K1 meson suggested by the SCALAR Collaboration from lattice QCD. The computations are conducted with the MILC Nf = 3 flavor gauge configurations at three lattice spacings: a≈0.15, 0.12, and 0.09 fm. 10.1088/1674-1137/39/8/083101
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
String formation beyond leading colour / Christiansen, Jesper ; Skands, Peter [arXiv:1505.01681] We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N C are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for “baryonic” configurations (e.g., two colours can combine coherently to form an anticolour). In e + e − collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/ N C 2 suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important 〈 p ⊥ 〉 ( n charged ) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p ⊥ spectra remains challenging to explain. 10.1007/JHEP08(2015)003
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
Resonant Higgs boson pair production in the h h → b b ¯ W W → b b ¯ ℓ + ν ℓ − ν ¯ $$ hh\to b\overline{b}\ WW\to b\overline{b}{\ell}^{+}\nu {\ell}^{-}\overline{\nu} $$ decay channel / Lozano, Víctor ; Moreno, Jesús ; Park, Chan [arXiv:1501.03799] The addition of a scalar singlet provides one of the simplest extensions of the Standard Model. In this work we briefly review the latest constraints on the mass and mixing of the new Higgs boson and study its production and decay at the LHC. We mainly focus on double Higgs production in the h h → b b ¯ W W → b b ¯ ℓ + ν ℓ − ν ¯ $$ hh\to b\overline{b}WW\to b\overline{b}{\ell}^{+}\nu {\ell}^{-}\overline{\nu} $$ decay channel. This decay is found to be efficient in a region of masses of the heavy Higgs boson of 260-500 GeV, so it is complementary to the 4 b channel, more efficient for Higgs bosons with masses greater than 500 GeV. We analyse this di-leptonic decay channel in detail using kinematic variables such as M T2 and the M T2 -assisted on-shell reconstruction of invisible momenta. Using proper cuts, a significance of ∼ 3 σ for 3000 fb −1 can be achieved at the 14 TeV LHC for m H = 260-400 GeV if the mixing is close to its present limit and BR( H → hh ) ≈ 1. Smaller values for the mixing would require combining various decay channels in order to reach a similar significance. The complementarity among H → hh , H → ZZ and H → WW channels is studied for arbitrary BR( H → hh ) values. 10.1007/JHEP08(2015)004
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
Field theory on Newton-Cartan backgrounds and symmetries of the Lifshitz vacuum / Hartong, Jelle ; Kiritsis, Elias ; Obers, Niels [arXiv:1502.00228] Holography for Lifshitz space-times corresponds to dual field theories on a fixed torsional Newton-Cartan (TNC) background. We examine the coupling of non-relativistic field theories to TNC backgrounds and uncover a novel mechanism by which a global U(1) can become local. This involves the TNC vector M μ which sources a particle number current, and which for flat NC space-time satisfies M μ = ∂ μ M with a Schrödinger symmetry realized on M . We discuss various toy model field theories on flat NC space-time for which the new mechanism leads to extra global space-time symmetries beyond the generic Lifshitz symmetry, allowing for an enhancement to Schrödinger symmetry. On the holographic side, the source M also appears in the Lifshitz vacuum with exactly the same properties as for flat NC space-time. In particular, the bulk diffeomorphisms that preserve the boundary conditions realize a Schrödinger algebra on M , allowing for a conserved particle number current. Finally, we present a probe action for a complex scalar field on the Lifshitz vacuum, which exhibits Schrödinger invariance in the same manner as seen in the field theory models. 10.1007/JHEP08(2015)006
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
Supersymmetric gauge theories on five-manifolds / Alday, Luis ; Genolini, Pietro ; Fluder, Martin ; Richmond, Paul ; et al [arXiv:1503.09090] We construct rigid supersymmetric gauge theories on Riemannian five-manifolds. We follow a holographic approach, realizing the manifold as the conformal boundary of a six-dimensional bulk supergravity solution. This leads to a systematic classification of five-dimensional supersymmetric backgrounds with gravity duals. We show that the background metric is furnished with a conformal Killing vector, which generates a transversely holomorphic foliation with a transverse Hermitian structure. Moreover, we prove that any such metric defines a supersymmetric background. Finally, we construct supersymmetric Lagrangians for gauge theories coupled to arbitrary matter on such backgrounds. 10.1007/JHEP08(2015)007
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
Comments on the Nekrasov-type formula for E-string theory / Ishii, Takenori [arXiv:1506.05582] We generalize our previous result [T. Ishii and K. Sakai, J. High Energy Phys. 02 , 087 (2014) [arXiv:1312.1050 [hep-th]]] to cases with three and four Wilson lines. We show that the Nekrasov-type formula for E-string theory is valid for these cases and that the Seiberg–Witten curves are reproduced from the formula. In addition, we show the dependence of the Seiberg–Witten curve on the Wilson lines. 10.1093/ptep/ptv102
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:54
Tao probing the end of the world / Kim, Sung-Soo ; Taki, Masato ; Yagi, Futoshi [arXiv:1504.03672] We introduce a new type IIB 5-brane description for the E-string theory which is the world-volume theory on the M5-brane probing the end of the world M9-brane. The E-string in the new realization is depicted as spiral 5-branes web equipped with the cyclic structure which is key to uplifting to six dimensions. Utilizing the topological vertex to the 5-brane web configuration enables us to write down a combinatorial formula for the generating function of the E-string elliptic genera, namely the full partition function of topological strings on the local K3 surface. 10.1093/ptep/ptv108
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records
2015-10-13
20:53
Higher spin entanglement and W N $$ {\mathcal{W}}_{\mathrm{N}} $$ conformal blocks / Boer, Jan ; Castro, Alejandra ; Hijano, Eliot ; Jottar, Juan ; et al [arXiv:1412.7520] Two-dimensional conformal field theories with extended W $$ \mathcal{W} $$ -symmetry algebras have dual descriptions in terms of weakly coupled higher spin gravity in AdS 3 at large central charge. Observables that can be computed and compared in the two descriptions include Rényi and entanglement entropies, and correlation functions of local operators. We develop techniques for computing these, in a manner that sheds light on when and why one can expect agreement between such quantities on each side of the duality. We set up the computation of excited state Rényi entropies in the bulk in terms of Chern-Simons connections, and show how this directly parallels the CFT computation of correlation functions. More generally, we consider the vacuum conformal block for general operators with Δ ∼ c . When two of the operators obey Δ c ≪ 1 $$ \frac{\varDelta }{c}\ll 1 $$ , we show by explicit computation that the vacuum conformal block is computed by a bulk Wilson line probing an asymptotically AdS 3 background with higher spin fields excited, the latter emerging as the effective bulk description of the excited state produced by the heavy operators. Among other things, this puts a previous proposal for computing higher spin entanglement entropy via Wilson lines on firmer footing, and clarifies its relation to CFT. We also study the corresponding computation in Toda theory and find that this provides yet another independent way to arrive at the same result. 10.1007/JHEP07(2015)168
Fulltext: Download fulltextPDF Download fulltextXML;
Detailed record - Similar records