18367952
The asymptotic spectrum of the = 4 super-Yang-Mills spin chain
In this paper we discuss the asymptotic spectrum of the spin chain description of planar = 4 SUSY Yang-Mills. The states appearing in the spectrum belong to irreducible representations of the unbroken supersymmetry SU(2|2) × SU(2|2) with non-trivial extra central extensions. The elementary magnon corresponds to the bifundamental representation while boundstates of Q magnons form a certain short representation of dimension 16Q2. Generalising the Beisert's analysis of the Q = 1 case, we derive the exact dispersion relation for these states by purely group theoretic means.
119588455
A new 2d/4d duality via integrability
We prove a duality, recently conjectured in arXiv:1103.5726, which relates the F-terms of supersymmetric gauge theories defined in two and four dimensions respectively. The proof proceeds by a saddle point analysis of the four-dimensional partition function in the Nekrasov-Shatashvili limit. At special quantized values of the Coulomb branch moduli, the saddle point condition becomes the Bethe Ansatz Equation of the SL(2) Heisenberg spin chain which coincides with the F-term equation of the dual two-dimensional theory. The on-shell values of the superpotential in the two theories are shown to coincide in corresponding vacua. We also identify two-dimensional duals for a large set of quiver gauge theories in four dimensions and generalize our proof to these cases.
17544914
Precision test of AdS/CFT in Lunin-Maldacena background
We obtain the solutions and explicitly calculate the energy for a class of two-spin semiclassical string states in the Lunin-Maldacena background. These configurations are the β-deformed versions of the folded string solutions in AdS5 × S5 background. They correspond to certain single trace operators in the = 1 superconformal β deformation of = 4 Yang-Mills. We calculate the one loop anomalous dimension for the dual single trace operators from the associated twisted spin chain with a general two-cut distribution of Bethe roots. Our results show a striking match between the two calculations. We demonstrate the natural identification of parameters on the two sides of the analysis, and explain the significance of the Virasoro constraint associated with the winding motion of semiclassical strings from the perspective of the spin chain solution.
17995666
On the scattering of magnon boundstates
We study the scattering of magnon boundstates in the spin-chain description of planar = 4 SUSY Yang-Mills. Starting from the conjectured exact S-matrix for magnons in the SU(2) sector, we calculate the corresponding S-matrix for boundstates with an arbitrary number of constituent magnons. The resulting expression has an interesting analytic structure with both simple and double poles. We also calculate the semiclassical S-matrix for the scattering of the corresponding excitations on the string worldsheet known as Dyonic Giant Magnons. We find precise agreement with the magnon boundstate S-matrix in the limit of large 't Hooft coupling.
119200064
Notes on wall crossing and instanton in compactified gauge theory with matter
We study the quantum effects on the Coulomb branch of $ \mathcal{N} = 2 $ SU(2) super-symmetric Yang-Mills with fundamental matters compactified on $ {\mathbb{R}^3} \times {S^1} $, and extract the explicit perturbative and leading non-perturbative corrections to the moduli space metric predicted from the recent work of Gaiotto, Moore and Neitzke on wall-crossing [1]. We verify the predicted metric by computing the leading weak coupling instanton contribution to the four fermion correlation using standard field theory techniques, and demonstrate perfect agreement. We also demonstrate how previously known three dimensional quantities can be recovered in appropriate small radius limit, and provide a simple geometric picture from brane construction.
118687033
Moduli space and wall-crossing formulae in higher-rank gauge theories
A bstractWe study the interplay between wall-crossing in four-dimensional gauge theory and instanton contributions to the moduli space metric of the same theory on $\mathbb{R}^{3}\times S^{1}$. We consider $\mathcal{N}=2$ SUSY Yang-Mills with gauge group SU(n) and focus on walls of marginal stability which extend to weak coupling. By comparison with explicit field theory results we verify the Kontsevich-Soibelman formula for the change in the BPS spectrum at these walls and check the smoothness of the metric in the corresponding compactified theory. We also verify in detail the predictions for the one instanton contribution to the metric coming from the non-linear integral equations of Gaiotto, Moore and Nietzke.
119166024
Heterotic surface defects and dualities from 2d/4d indices
A bstractStarting with the superconformal indices for 4d N=2$$ \mathcal{N}=2 $$ and N=1$$ \mathcal{N}=1 $$ supersymmetric gauge theories, that are related by superpotential deformation, we perform the contour integrations and isolate the residue contributions which can be attributed to the surface defects. These defects can be interpreted as the IR limit of dynamical vortices. Given the 2d N=22$$ \mathcal{N}=\left(2,2\right) $$ and N=02$$ \mathcal{N}=\left(0,2\right) $$ world sheet theories for these surface defects, we then verify this statement by explicitly computing their elliptic genera and identifying their fugacity parameters through superconformal algebras. We show them precisely match, hence extend previous prescriptions for inserting surface defects into 4d supersymmetric partition functions to N=1$$ \mathcal{N}=1 $$ setting. We also study how 4d N=1$$ \mathcal{N}=1 $$ IR dualities descend into the N=02$$ \mathcal{N}=\left(0,2\right) $$ world sheet theories of their surface defects, and extend the N=22$$ \mathcal{N}=\left(2,2\right) $$ triality observed earlier to other N=02$$ \mathcal{N}=\left(0,2\right) $$ surface defects unrelated to dynamical vortices.
55556108
Extracting interstellar diffuse absorption bands from cool star spectra - Application to bulge clump giants in Baade’s window
Interstellar diffuse bands are usually extracted from hot star spectra because they are characterized by smooth continua. It introduces a strong limitation on the number of available targets, and reduces potential studies of the IS matter and the use of absorptions for cloud mapping. We have developed a new automatic fitting method appropriate to interstellar absorptions in spectra of cool stars that possess stellar atmospheric parameters. We applied this method to the extraction of three DIBs in high resolution VLT FLAMES/GIRAFFE spectra of red clump stars from the bulge. By combining all stellar synthetic spectra, HITRAN-LBLRTM atmospheric transmission spectra and diffuse band empirical absorption profiles, we determine the 6196, 6204, and 6284 A DIB strength toward the 219 target stars and discuss the sources of uncertainties. In order to test the sensitivity of the DIB extraction, we intercompare the three results and compare the DIB equivalent widths with the reddening derived from an independent extinction map based on OGLE photometric data. Most stellar spectra could be well reproduced by the composite stellar, atmospheric and interstellar models. Measurement uncertainties on the EWs are smaller for the broad and strong 6284 A DIB, and are of the order of 10-15%. Uncertainties on the two narrow and weaker DIBs are larger, as expected, and found to be highly variable from one target to the other. They strongly depend on the radial velocity of the star . DIB-DIB correlations among the three bands demonstrate that a meaningful signal is extracted. For the 6284 and 6204 A DIBs, the star-to-star variability of the equivalent width (EW) also reflects features of the OGLE extinction map...
120528491
Tau-Charm factory project at Beijing
Abstract The Tau-Charm Factory (TCF) is a proposed high luminosity e + e − collider at the threshold region of the production of τ and charm. It could provide many precision measurements and search for new phenomena in the flavor physics. IHEP, Beijing, is an ideal cite to build a TCF. The status of the feasibility study of Beijing Tau-Charm Factory (BTCF) is reported.
119197432
Proton decay and the origin of quark and lepton mixing
A bstractIt was recently proposed that all flavor mixing has a single source, namely the mixing of the three quark and lepton families with “extra” vectorlike fermions in 5 + $ \overline{5} $ multiplets of SU(5). This was shown to lead to several testable predictions including neutrino masses and CP-violating phases. Here it is shown that the mixing angles within grand unified fermion multiplets are also predicted. Proton decay branching ratios would thus give several independent tests of the model. Certain model parameters could be determined independently from the quark and lepton spectrum and from proton decay.
28336224
Search for physics beyond the standard model in events with two leptons, jets, and missing transverse momentum in pp collisions at s$$ \sqrt{s} $$ = 8 TeV
A bstractA search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 fb−1 of proton-proton collisions at s$$ \sqrt{s} $$ = 8 TeV collected with the CMS detector at the CERN LHC in 2012. The analysis focuses on searches for a kinematic edge in the invariant mass distribution of the oppositesign same-flavor lepton pair and for final states with an on-shell Z boson. The observations are consistent with expectations from standard model processes and are interpreted in terms of upper limits on the production of supersymmetric particles.
