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Chiral algebras of class S
http://cds.cern.ch/record/1752414
Fourdimensional N=2 superconformal field theories have families of protected correlation functions that possess the structure of twodimensional chiral algebras. In this paper, we explore the chiral algebras that arise in this manner in the context of theories of class S. The class S duality web implies nontrivial associativity properties for the corresponding chiral algebras, the structure of which is best summarized in the language of generalized topological quantum field theory. We make a number of conjectures regarding the chiral algebras associated to various strongly coupled fixed points.
Beem, Christopher
Fri, 29 Aug 2014 05:39:27 GMT
http://cds.cern.ch/record/1752414

Catching sparks from wellforged neutralinos
http://cds.cern.ch/record/1752392
In this paper we present a new search technique for electroweakinos, the superpartners of electroweak gauge and Higgs bosons, based on final states with missing transverse energy, a photon, and a dilepton pair, $\ell^+\,\ell^ + \gamma + \displaystyle{\not} E_T$. Unlike traditional electroweakino searches, which perform best when $m_{\widetilde{\chi}^0_{2,3}}  m_{\widetilde{\chi}^0_1}, m_{\widetilde{\chi}^{\pm}}  m_{\widetilde{\chi}^0_1} > m_Z$, our search favors nearly degenerate spectra; degenerate electroweakinos typically have a larger branching ratio to photons, and the cut $m_{\ell\ell} \ll m_Z$ effectively removes onshell Z boson backgrounds while retaining the signal. This feature makes our technique optimal for `welltempered' scenarios, where the dark matter relic abundance is achieved with interelectroweakino splittings of $\sim 20  70\,\text{GeV}$. Additionally, our strategy applies to a wider range of scenarios where the lightest neutralinos are almost degenerate, but only make up a subdominant component of the dark matter  a spectrum we dub `wellforged'. Focusing on binoHiggsino admixtures, we present optimal cuts and expected efficiencies for several benchmark scenarios. We find binoHiggsino mixtures with $m_{\widetilde{\chi}^0_{2,3}} \lesssim 190\,\text{GeV}$ and $m_{\widetilde{\chi}^0_{2,3}}  m_{\widetilde{\chi}^0_1} \cong 30\,\text{GeV}$ can be uncovered after roughly $600\,\text{fb}^{1}$ of luminosity at the 14 TeV LHC. Scenarios with lighter states require less data for discovery, while scenarios with heavier states or larger mass splittings are harder to discriminate from the background and require more data. Unlike many searches for supersymmetry, electroweakino searches are one area where the high luminosity of the next LHC run, rather than the increased energy, is crucial for discovery.
Bramante, Joseph
Fri, 29 Aug 2014 05:38:53 GMT
http://cds.cern.ch/record/1752392

A perturbative approach to the hydrodynamics of heavy ion collisions
http://cds.cern.ch/record/1752386
Initial fluctuations in hydrodynamic fields such as energy density or flow velocity give access to understanding initial state and equilibration physics as well as thermodynamic and transport properties. We provide evidence that the fluid dynamic propagation of fluctuations of realistic size can be based on a backgroundfluctuation splitting and a systematic perturbative expansion in the fluctuating fields. Initial conditions are characterized by a BesselFourier expansion for single events, eventbyevent correlations and probability distributions. The evolution equations can be solved orderbyorder in the expansion which allows to study the fluid dynamical propagation of single modes, the study of interaction effects between modes, the determination of the associated particle spectra and the generalization of the whole program to eventbyevent correlations and distributions.
Floerchinger, Stefan
Fri, 29 Aug 2014 05:38:50 GMT
http://cds.cern.ch/record/1752386

GaussBonnet assisted Braneworld Inflation in light of BICEP2 and Planck
http://cds.cern.ch/record/1752311
Motivated by the idea that quantum gravity corrections usually suppress the power of the scalar primordial spectrum (Emode) more than the power of the tensor primordial spectrum (Bmode), in this Letter we construct a concrete gravitational theory in fivedimensions for which $V(\phi)\propto \phi^n$type inflation ($n\ge 1$) generates an appropriate tensortoscalar ratio that may be compatible with the BICEP2 and Planck data together. The true nature of gravity is fivedimensional and described by the action $S = \int d^5{x} \sqrt{g} M^3 \left( 6\lambda M^2 + R + \alpha M^{2} {\cal R}^2\right)$ where $M$ is the fivedimensional Planck mass and ${\cal R}^2=R^24 R_{ab} R^{ab} + R_{abcd} R^{abcd}$ is the GaussBonnet (GB) term. The fivedimensional `bulk' spacetime is antide Sitter ($\lambda<0$) for which inflation ends naturally. The effects of ${\cal R}^2$ term on the magnitudes of scalar and tensor fluctuations and spectral indices are shown to be important at the energy scale of inflation. For GBassisted $m^2\phi^2$inflation, inflationary constraints from BICEP2 and Planck, such as, $n_s\simeq 0.9603~(\pm 0.0073)$, $r=0.16~(+0.060.05)$ and $V_*^{1/4} \sim 1.5\times 10^{16}~GeV$ are all satisfied for $ (\lambda \alpha) \simeq (3300)\times 10^{5}$.
Neupane, Ishwaree P
Fri, 29 Aug 2014 05:36:20 GMT
http://cds.cern.ch/record/1752311

SIMPle Dark Matter: SelfInteractions and keV Lines
http://cds.cern.ch/record/1752287
We consider a simple supersymmetric hidden sector: pure SU(N) gauge theory. Dark matter is made up of hidden glueballinos with mass $m_X$ and hidden glueballs with mass near the confinement scale $\Lambda$. For $m_X \sim 1~\text{TeV}$ and $\Lambda \sim 100~\text{MeV}$, the glueballinos freeze out with the correct relic density and selfinteract through glueball exchange to resolve smallscale structure puzzles. An immediate consequence is that the glueballino spectrum has a hyperfine splitting of order $\Lambda^2 / m_X \sim 10~\text{keV}$. We show that the radiative decays of the excited state can explain the observed 3.5 keV Xray line signal from clusters of galaxies, Andromeda, and the Milky Way.
Boddy, Kimberly K
Fri, 29 Aug 2014 05:36:18 GMT
http://cds.cern.ch/record/1752287

Theory Summary and Prospects
http://cds.cern.ch/record/1751766
This talk reviews some of the theoretical progress and outstanding issues in QCD, flavour physics, Higgs and electroweak physics and the search for physics beyond the Standard Model at the Tevatron and the LHC, and previews some physics possibilities for future runs of the LHC and proposed future hadron colliders.
Ellis, John
Tue, 26 Aug 2014 05:53:00 GMT
http://cds.cern.ch/record/1751766

W gamma production in hadronic collisions using the POWHEG+MiNLO method
http://cds.cern.ch/record/1751762
We detail a calculation of W gamma production in hadronic collision, at NexttoLeading Order (NLO) QCD interfaced to a shower generator according to the POWHEG prescription supplemented with the MiNLO procedure. The fixed order result is matched to an interleaved QCD+QED parton shower, in such a way that the contribution arising from hadron fragmentation into photons is fully modeled. In general, our calculation illustrates a new approach to the fully exclusive simulation of prompt photon production processes accurate at the NLO level in QCD. We compare our predictions to those of the NLO program MCFM, which treats the fragmentation contribution in terms of photon fragmentation functions. We also perform comparisons to available LHC data at 7 TeV, for which we observe good agreement, and provide phenomenological results for physics studies of the W gamma production process at the Run II of the LHC. The new tool, which includes W leptonic decays and the contribution of anomalous gauge couplings, allows a fully exclusive, hadronlevel description of the W gamma process, and is publicly available at the repository of the POWHEG BOX. Our approach can be easily adapted to deal with other relevant isolated photon production processes in hadronic collisions.
Barze, Luca
Tue, 26 Aug 2014 05:52:59 GMT
http://cds.cern.ch/record/1751762

On the Flavor Structure of Natural Composite Higgs Models & Top Flavor Violation
http://cds.cern.ch/record/1751232
We explore the up flavor structure of composite pseudo NambuGoldstoneboson Higgs models, where we focus on the flavor anarchic minimal $SO(5)$ case. We identify the different sources of flavor violation in this framework and emphasise the differences from the anarchic RandallSundrum scenario. In particular, the fact that the flavor symmetry does not commute with the symmetries that stabilize the Higgs potential may constrain the flavor structure of the theory. In addition, we consider the interplay between the fine tuning of the model and flavor violation. We find that generically the tuning of this class of models is worsen in the anarchic case due to the contributions from the additional fermion resonances. We show that, even in the presence of custodial symmetry, large top flavor violating rate are naturally expected. In particular, $t\to cZ$ branching ratio of order of $10^{5}$ is generic for this class of models. Thus, this framework can be tested in the next run of the LHC as well as in other future colliders. We also find that the top flavor violation is weakly correlated with the increase amount of fine tuning. Finally, other related flavor violation effects, such as $t \to ch$ and in the $D$ system, are found to be too small to be observed by the current and near future colliders.
Azatov, Aleksandr
Fri, 22 Aug 2014 08:14:03 GMT
http://cds.cern.ch/record/1751232

The chiral phase transition in twoflavor QCD from imaginary chemical potential
http://cds.cern.ch/record/1751225
We investigate the order of the finite temperature chiral symmetry restoration transition for QCD with two massless fermions, by using a novel method, based on simulating imaginary values of the quark chemical potential $\mu=i\mu_i,\mu_i\in\mathbb{R}$. Our method exploits the fact that, for low enough quark mass $m$ and large enough chemical potential $\mu_i$, the chiral transition is decidedly first order, then turning into crossover at a critical mass $m_c(\mu)$. It is thus possible to determine the critical line in the $m  \mu^2$ plane, which can be safely extrapolated to the chiral limit by taking advantage of the known tricritical indices governing its shape. We test this method with standard staggered fermions and the result of our simulations is that $m_c(\mu=0)$ is positive, so that the phase transition at zero density is definitely first order in the chiral limit, on our coarse $N_t=4$ lattices with $a\simeq 0.3\,\mathrm{fm}$.
Bonati, Claudio
Fri, 22 Aug 2014 08:13:11 GMT
http://cds.cern.ch/record/1751225

Dark matter direct detection constraints from gauge bosons loops
http://cds.cern.ch/record/1751207
While many interactions of dark matter (DM) with the standard model (SM) affect direct detection and LHC searches, there are only a few operators generating annihilation of DM into photons. All of these operators, except four of them, give rise to unsuppressed rates, rendering indirect detection superior to other search strategies. For two of the four effective interactions with velocitysuppressed annihilation cross sections, we identify a new type of loop effect which significantly enhances the associated direct detection rates. As a result, relevant constraints from nextgeneration direct detection experiments on DMSM interactions, so far only bounded by the LHC, are obtained.
Crivellin, Andreas
Fri, 22 Aug 2014 06:26:30 GMT
http://cds.cern.ch/record/1751207

EFT Beyond the Horizon: Stochastic Inflation and How Primordial Quantum Fluctuations Go Classical
http://cds.cern.ch/record/1751142
We identify the effective theory describing inflationary superHubble scales and show it to be a special case of effective field theories appropriate to open systems. Open systems allow information to be exchanged between the degrees of freedom of interest and those that are integrated out, such as for particles moving through a fluid. Strictly speaking they cannot in general be described by an effective lagrangian; rather the appropriate `lowenergy' limit is instead a Lindblad equation describing the evolution of the density matrix of the slow degrees of freedom. We derive the equation relevant to superHubble modes of quantum fields in nearde Sitter spacetimes and derive two implications. We show the evolution of the diagonal densitymatrix elements quickly approaches the FokkerPlanck equation of Starobinsky's stochastic inflationary picture. This provides an alternative firstprinciples derivation of this picture's stochastic noise and drift, as well as its leading corrections. (An application computes the noise for systems with a subluminal sound speed.) We argue that the presence of interactions drives the offdiagonal densitymatrix elements to zero in the field basis. This shows why the field basis is the `pointer basis' for the decoherence of primordial quantum fluctuations while they are outside the horizon, thus allowing them to reenter as classical fluctuations, as assumed when analyzing CMB data. The decoherence process is efficient, occurring after several Hubble times even for interactions as weak as gravitationalstrength. Crucially, the details of the interactions largely control only the decoherence time and not the nature of the final latetime stochastic state, much as interactions can control the equilibration time for thermal systems but are largely irrelevant to the properties of the resulting equilibrium state.
Burgess, C P
Fri, 22 Aug 2014 06:25:03 GMT
http://cds.cern.ch/record/1751142

Magnetization of fluid phonons and largescale curvature perturbations
http://cds.cern.ch/record/1751076
The quasinormal mode of a gravitating and magnetized fluid in a spatially flat, isotropic and homogeneous cosmological background is derived in the presence of the fluid sources of anisotropic stress and of the entropic fluctuations of the plasma. The obtained gaugeinvariant description involves a system of two coupled differential equations whose physical content is analyzed in all the most relevant situations. The Cauchy problem of largescale curvature perturbations during the radiation dominated stage of expansion can be neatly formulated and its general solution is shown to depend on five initial data assigned when the relevant physical wavelengths are larger than the particle horizon. The consequences of this approach are explored.
Giovannini, Massimo
Fri, 22 Aug 2014 06:24:55 GMT
http://cds.cern.ch/record/1751076

Muon g2 Anomaly and Dark Leptonic Gauge Boson
http://cds.cern.ch/record/1750835
One of the major motivations to search for a dark gauge boson of MeVGeV scale is the longstanding muon g2 anomaly. Because of active searches such as fixed target experiments and rare meson decays, the muon g2 favored parameter region has been rapidly reduced. With the most recent data, it is practically excluded now in the popular dark photon model. We overview the issue and investigate a potentially alternative model based on the gauged lepton number or U(1)_L, which is under different experimental constraints.
Lee, HyeSung
Wed, 20 Aug 2014 05:34:22 GMT
http://cds.cern.ch/record/1750835

Gravity and axions from a random UV QFT
http://cds.cern.ch/record/1750573
It is postulated that the UV QFT is enormous and random. The coupling of the Standard Model to such QFT is analyzed. It is argued that massless 4d gravity and axions are general avatars of the postulate. The equivalence principle emerges naturally as well as a concrete set of sources for its breaking. The axion scale is related to the 4d Planck scale as $f=M_P/N$, where $N$ is the "number of colors" of the (almost) hidden UV CFT.
Kiritsis, Elias
Tue, 19 Aug 2014 05:40:45 GMT
http://cds.cern.ch/record/1750573

The NUHM2 after LHC Run 1
http://cds.cern.ch/record/1750563
We make a frequentist analysis of the parameter space of the NUHM2, in which the soft supersymmetry (SUSY)breaking contributions to the masses of the two Higgs multiplets, $m^2_{H_{u,d}}$, vary independently from the universal soft SUSYbreaking contributions $m^2_0$ to the masses of squarks and sleptons. Our analysis uses the MultiNest sampling algorithm with over $4 \times 10^8$ points to sample the NUHM2 parameter space. It includes the ATLAS and CMS Higgs mass measurements as well as their searches for supersymmetric jets + MET signals using the full LHC Run~1 data, the measurements of $B_s \to \mu^+ \mu^$ by LHCb and CMS together with other Bphysics observables, electroweak precision observables and the XENON100 and LUX searches for spinindependent dark matter scattering. We find that the preferred regions of the NUHM2 parameter space have negative SUSYbreaking scalar masses squared for squarks and sleptons, $m_0^2 < 0$, as well as $m^2_{H_u} < m^2_{H_d} < 0$. The tension present in the CMSSM and NUHM1 between the supersymmetric interpretation of $g_\mu  2$ and the absence to date of SUSY at the LHC is not significantly alleviated in the NUHM2. We find that the minimum $\chi^2 = 32.5$ with 21 degrees of freedom (dof) in the NUHM2, to be compared with $\chi^2/{\rm dof} = 35.0/23$ in the CMSSM, and $\chi^2/{\rm dof} = 32.7/22$ in the NUHM1. We find that the onedimensional likelihood functions for sparticle masses and other observables are similar to those found previously in the CMSSM and NUHM1.
Buchmueller, O
Tue, 19 Aug 2014 05:39:57 GMT
http://cds.cern.ch/record/1750563

Pinning down compressed supersymmetric scenarios with monotop probes
http://cds.cern.ch/record/1750550
We investigate the sensitivity of the Large Hadron Collider to compressed supersymmetric setups by means of monotop events where a single top quark is produced in association with missing transverse energy. Our prospective study relies on Monte Carlo simulations of 10 fb$^{1}$ of protonproton collisions at a centreofmass energy of 14 TeV and considers both leptonic and hadronic monotop decays. We present analysis strategies sensitive to regions of the supersymmetric parameter space which feature small superparticle mass splittings and illustrate their strengths in the context of a particular set of benchmark scenarios.
Fuks, Benjamin
Tue, 19 Aug 2014 05:39:51 GMT
http://cds.cern.ch/record/1750550

Cosmology with Nilpotent Superfields
http://cds.cern.ch/record/1750546
We discuss N=1 supergravity inflationary models based on two chiral multiplets, the inflaton and the goldstino superfield. Using superconformal methods for these models, we propose to replace the unconstrained chiral goldstino multiplet by the nilpotent one associated with nonlinearly realized supersymmetry of the VolkovAkulov type. In the new cosmological models, the sgoldstino is proportional to a bilinear combination of fermionic goldstinos. It does not acquire any vev, does nor require stabilization, and does not affect the cosmological evolution. We explain a universal relation of these new models to kappasymmetric superDpbrane actions. This modification significantly simplifies a broad class of the presently existing inflationary models based on supergravity and string theory, including the simplest versions of chaotic inflation, the Starobinsky model, a broad class of cosmological attractors, the Higgs inflation, and much more. In particular, this is a step towards a fully supersymmetric version of the string theory axion monodromy inflation. The new construction serves as a simple and manifestly supersymmetric uplifting tool in the KKLTtype string theory landscape.
Ferrara, Sergio
Tue, 19 Aug 2014 05:39:31 GMT
http://cds.cern.ch/record/1750546

Maximally Symmetric Two Higgs Doublet Model with Natural Standard Model Alignment
http://cds.cern.ch/record/1750101
We study the Higgs mass spectrum as predicted by a Maximally Symmetric Two Higgs Doublet Model (MS2HDM) potential based on the SO(5) group, softly broken by bilinear Higgs mass terms. We show that the lightest Higgs sector resulting from this MS2HDM becomes naturally aligned with that of the Standard Model (SM), independently of the charged Higgs boson mass and $\tan \beta$. Nevertheless, renormalization group effects due to the hypercharge gauge coupling $g'$ and thirdgeneration Yukawa couplings may break sizeably this SM alignment, along with the custodial symmetry inherited by the SO(5) group. Using the current Higgs signal strength data from the LHC, which disfavour large deviations from the SM alignment limit, we derive lower mass bounds on the heavy Higgs sector as a function of $\tan\beta$, which can be stronger than the existing limits for a wide range of parameters. In particular, we propose a new collider signal based on the observation of four top quarks to directly probe the heavy Higgs sector of the MS2HDM during the runII phase of the LHC.
Dev, P S Bhupal
Fri, 15 Aug 2014 09:21:16 GMT
http://cds.cern.ch/record/1750101

Structure formation with massive neutrinos: going beyond linear theory
http://cds.cern.ch/record/1750009
We compute nonlinear corrections to the matter power spectrum taking the time and scaledependent freestreaming length of neutrinos into account. We adopt a hybrid scheme that matches the full Boltzmann hierarchy to an effective twofluid description at an intermediate redshift. The nonlinearities in the neutrino component are taken into account by using an extension of the timeflow framework. We point out that this remedies a spurious behaviour that occurs when neglecting nonlinear terms for neutrinos. This behaviour is related to how efficiently short modes decouple from long modes and can be traced back to the violation of momentum conservation if neutrinos are treated linearly. Furthermore, we compare our results at next to leading order to various other methods and quantify the accuracy of the fluid description. Due to the correct decoupling behaviour of short modes, the twofluid scheme is a suitable starting point to compute higher orders in perturbations or for resummation methods.
Blas, Diego
Fri, 15 Aug 2014 09:19:13 GMT
http://cds.cern.ch/record/1750009

A closer look at the possible CMS signal of a new gauge boson
http://cds.cern.ch/record/1748879
The CMS collaboration has recently reported a 2.8$\sigma$ excess of $eejj$ events with an invariant mass around 2 TeV. This observation can be explained in the context of standard model extensions with new gauge bosons $W'$, $Z'$ and heavy neutrinos coupling (mainly) to the electron. We discuss additional signals that allow to confirm or discard the $W'$ and $Z'$ hypotheses.
AguilarSaavedra, J A
Tue, 12 Aug 2014 10:11:32 GMT
http://cds.cern.ch/record/1748879

Interplay between hydrodynamics and jets
http://cds.cern.ch/record/1747906
By combining the jet quenching Monte Carlo JEWEL with a realistic hydrodynamic model for the background we investigate the sensitivity of jet observables to details of the medium model and quantify the influence of the energy and momentum lost by jets on the background evolution. On the level of event averaged source terms the effects are small and are caused mainly by the momentum transfer.
Zapp, Korinna C
Wed, 06 Aug 2014 02:11:06 GMT
http://cds.cern.ch/record/1747906

Scattering amplitudes in N=2 MaxwellEinstein and YangMills/Einstein supergravity
http://cds.cern.ch/record/1747704
We expose a doublecopy structure in the scattering amplitudes of the generic Jordan family of N=2 MaxwellEinstein and YangMills/Einstein supergravity theories in four and five dimensions. The MaxwellEinstein supergravity amplitudes are obtained through the color/kinematics duality as a product of two gaugetheory factors; one originating from pure N=2 superYangMills theory and the other from the dimensional reduction of a bosonic higherdimensional pure YangMills theory. We identify a specific symplectic frame in four dimensions for which the onshell fields and amplitudes from the doublecopy construction can be identified with the ones obtained from the supergravity Lagrangian and Feynmanrule computations. The YangMills/Einstein supergravity theories are obtained by gauging a compact subgroup of the isometry group of their MaxwellEinstein counterparts. For the generic Jordan family this process is identified with the introduction of cubic scalar couplings on the bosonic gaugetheory side, which through the double copy are responsible for the nonabelian vector interactions in the supergravity theory. As a demonstration of the power of this structure, we present explicit computations at treelevel and one loop. The doublecopy construction allows us to obtain compact expressions for the supergravity superamplitudes which are naturally organized as polynomials in the gauge coupling constant.
Chiodaroli, Marco
Tue, 05 Aug 2014 02:15:40 GMT
http://cds.cern.ch/record/1747704

String Resonances at Hadron Colliders
http://cds.cern.ch/record/1746912
[Abridged] We consider extensions of the standard model based on open strings ending on Dbranes. Assuming that the fundamental string mass scale M_s is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HLLHC run (3000 fb^{1}) with \sqrt{s} = 14 TeV, and at potential future pp colliders, HELHC and VLHC, operating at \sqrt{s} = 33 and 100 TeV, respectively. In such Dbrane constructions, the dominant contributions to fullfledged string amplitudes for all the common QCD parton subprocesses leading to dijets and \gamma + jet are completely independent of the details of compactification, and can be evaluated in a parameterfree manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV), lowest massive Regge excitations are open to discovery at 5\sigma in dijet (\gamma + jet) HLLHC data. We also show that for n=1, the dijet discovery potential at HELHC and VLHC exceedingly improves: up to 15 TeV and 41 TeV, respectively. To compute the signaltonoise ratio for n=2 resonances, we first carry out a complete calculation of all relevant decay widths of the second massive level string states. We demonstrate that for string scales M_s <~ 10.5 TeV (M_s <~ 28 TeV), detection of n=2 Regge recurrences at HELHC (VLHC) would become the smoking gun for Dbrane string compactifications. Our calculations have been performed using a semianalytic parton model approach which is cross checked against an original software package. The string event generator interfaces with HERWIG and Pythia through BlackMax. The source code is publically available in the hepforge repository.
Anchordoqui, Luis A
Thu, 31 Jul 2014 02:20:23 GMT
http://cds.cern.ch/record/1746912

Precision predictions for direct gaugino and slepton production at the LHC
http://cds.cern.ch/record/1746903
The search for electroweak superpartners has recently moved to the centre of interest at the LHC. We provide the currently most precise theoretical predictions for these particles, use them to assess the precision of parton shower simulations, and reanalyse public experimental results assuming more general decompositions of gauginos and sleptons.
Fuks, B
Thu, 31 Jul 2014 02:20:19 GMT
http://cds.cern.ch/record/1746903

Generalised geometry for string corrections
http://cds.cern.ch/record/1746604
We present a general formalism for incorporating the string corrections in generalised geometry, which necessitates the extension of the generalised tangent bundle. Not only are such extensions obstructed, string symmetries and the existence of a welldefined effective action require a precise choice of the (generalised) connection. The action takes a universal form given by a generalised LichnerowitzBismut theorem. As examples of this construction we discuss the corrections linear in $\alpha'$ in heterotic strings and the absence of such corrections for type II theories.
Coimbra, AndrĂ©
Wed, 30 Jul 2014 02:17:24 GMT
http://cds.cern.ch/record/1746604