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Boosted Dark Matter Quarrying at Surface Neutrino Detectors
http://cds.cern.ch/record/2314657
We propose the idea of "Earth Shielding" to reject cosmic-ray backgrounds, in the search for boosted dark matter at surface neutrino detectors, resulting in the enhancement of the signal-to-background ratio. The identification of cosmic-originating rare signals, especially lacking features, at surface detectors is often considered hopeless due to a vast amount of cosmic-ray-induced background, hence underground experiments are better motivated to avoid such a challenge. We claim that surface detectors can attain remarkable sensitivities to even featureless signals, once restricting to events coming through the Earth from the opposite side of the detector location for the signals leaving appreciable tracks from which the source direction is inferred. By doing so, potential backgrounds in the signal region of interest can be substantially suppressed. To validate our claim, we study experimental reaches at several surface experiments such as SBN Program (MicroBooNE, ICARUS, and SBND) and ProtoDUNE for elastic boosted dark matter signatures stemming from the Galactic Center. We provide a systematic discussion on maximizing associated signal sensitivities.Kim, DoojinKong, KyoungchulPark, Jong-ChulShin, SeodongMon, 23 Apr 2018 13:01:08 GMT2018-04-19CERN-TH-2018-088http://cds.cern.ch/record/23146572018088Bottom-quark effects in Higgs production at intermediate transverse momentum
http://cds.cern.ch/record/2314656
We provide a precise description of the Higgs boson transverse momentum distribution including top and bottom quark contributions, that is valid for transverse momenta in the range mb < pt < mt, where mb and mt are the bottom and top quark masses. This description is based on a combination of fixed next-to-leading order (NLO) results with next-to-next-to-leading logarithmic (NNLL) transverse momentum resummation. We show that ambiguities in the resummation procedure for the b-quark loops are of the same order as the related fixed-order uncertainties. We conclude that the current uncertainty in the top-bottom interference contribution to the Higgs transverse momentum spectrum is O(20%).Caola, FabrizioLindert, Jonas M.Melnikov, KirillMonni, Pier FrancescoTancredi, LorenzoWever, ChristopherMon, 23 Apr 2018 13:00:42 GMT2018-04-20IPPP/18/27http://cds.cern.ch/record/2314656['IPPP/18/27']IPPP/18/27Systematic approximation of multi-scale Feynman integrals
http://cds.cern.ch/record/2314347
An algorithm for the systematic analytical approximation of multi-scale Feynman integrals is presented. The algorithm produces algebraic expressions as functions of the kinematical parameters and mass scales appearing in the Feynman integrals, allowing for fast numerical evaluation. The results are valid in all kinematical regions, both above and below thresholds, up to in principle arbitrary orders in the dimensional regulator. The scope of the algorithm is demonstrated by presenting results for selected two-loop three-point and four-point integrals with an internal mass scale that appear in the two-loop amplitudes for Higgs+jet production.Borowka, SophiaGehrmann, ThomasHulme, DanielFri, 20 Apr 2018 05:34:24 GMT2018-04-18CERN-TH-2018-078http://cds.cern.ch/record/23143472018078Holographic duals of 3d S-fold CFTs
http://cds.cern.ch/record/2314346
We construct non-geometric AdS$_4$ solutions of IIB string theory where the fields in overlapping patches are glued by elements of the S-duality group. We obtain them by suitable quotients of compact and non-compact geometric solutions. The quotient procedure suggests CFT duals as quiver theories with links involving the so-called $T[U(N)]$ theory. We test the validity of the non-geometric solutions (and of our proposed holographic duality) by computing the three-sphere partition function $Z$ of the CFTs. A first class of solutions is obtained by an S-duality quotient of Janus-type non-compact solutions and is dual to 3d $\mathcal{N}=4$ SCFTs; for these we manage to compute $Z$ of the dual CFT at finite $N$, and it agrees perfectly with the supergravity result in the large $N$ limit. A second class has five-branes, it is obtained by a M\"obius-like S-quotient of ordinary compact solutions and is dual to 3d $\mathcal{N}=3$ SCFTs. For these, $Z$ agrees with the supergravity result if one chooses the limit carefully so that the effect of the fivebranes does not backreact on the entire geometry. Other limits suggest the existence of IIA duals.Assel, BenjaminTomasiello, AlessandroFri, 20 Apr 2018 05:34:20 GMT2018-04-17CERN-TH-2018-087http://cds.cern.ch/record/23143462018087Higgs amplitudes from supersymmetric form factors Part II: $\mathcal{N}<4$ super Yang-Mills
http://cds.cern.ch/record/2313955
The study of form factors has many phenomenologically interesting applications, one of which is Higgs plus gluon amplitudes in QCD. Through effective field theory techniques these are related to form factors of various operators of increasing classical dimension. In this paper we extend our analysis of the first finite top-mass correction, arising from the operator ${\rm Tr} (F^3)$, from $\mathcal{N}=4$ super Yang-Mills to theories with $\mathcal{N}<4$, for the case of three gluons and up to two loops. We confirm our earlier result that the maximally transcendental part of the associated Catani remainder is universal and equal to that of the form factor of a protected trilinear operator in the maximally supersymmetric theory. The terms with lower transcendentality deviate from the $\mathcal{N}=4$ answer by a surprisingly small set of terms involving for example $\zeta_2$, $\zeta_3$ and simple powers of logarithms, for which we provide explicit expressions.Brandhuber, AndreasKostacinska, MartynaPenante, BrendaTravaglini, GabrieleWed, 18 Apr 2018 05:20:52 GMT2018-04-16QMUL-PH-18-05http://cds.cern.ch/record/23139551805Higgs amplitudes from supersymmetric form factors Part I: $\mathcal{N}=4$ super Yang-Mills
http://cds.cern.ch/record/2313954
In the large top-mass limit, Higgs plus multi-gluon amplitudes in QCD can be computed using an effective field theory. This approach turns the computation of such amplitudes into that of form factors of operators of increasing classical dimension. In this paper we focus on the first finite top-mass correction, arising from the operator ${\rm Tr}(F^3)$, up to two loops and three gluons. Setting up the calculation in the maximally supersymmetric theory requires identification of an appropriate supersymmetric completion of ${\rm Tr}(F^3)$, which we recognise as a descendant of the Konishi operator. We provide detailed computations for both this operator and the component operator ${\rm Tr}(F^3)$, preparing the ground for the calculation in $\mathcal{N}<4$, to be detailed in a companion paper. Our results for both operators are expressed in terms of a few universal functions of transcendental degree four and below, some of which have appeared in other contexts, hinting at universality of such quantities. An important feature of the result is a delicate cancellation of unphysical poles appearing in soft/collinear limits of the remainders which links terms of different transcendentality. Our calculation provides another example of the principle of maximal transcendentality for observables with non-trivial kinematic dependence.Brandhuber, AndreasKostacinska, MartynaPenante, BrendaTravaglini, GabrieleWed, 18 Apr 2018 05:20:47 GMT2018-04-16QMUL-PH-18-01http://cds.cern.ch/record/23139541801Infrared Resummation for Biased Tracers in Redshift Space
http://cds.cern.ch/record/2313953
We incorporate the effects of redshift space distortions and non-linear bias in time-sliced perturbation theory (TSPT). This is done via a new method that allows to map cosmological correlation functions from real to redshift space. This mapping preserves a transparent infrared (IR) structure of the theory and provides us with an efficient tool to study non-linear infrared effects altering the pattern of baryon acoustic oscillations (BAO) in redshift space. We give an accurate description of the BAO by means of a systematic resummation of Feynman diagrams guided by well-defined power counting rules. This establishes IR resummation within TSPT as a robust and complete procedure and provides a consistent theoretical model for the BAO feature in the statistics of biased tracers in redshift space.Ivanov, Mikhail M.Sibiryakov, SergeyWed, 18 Apr 2018 05:20:42 GMT2018-04-13CERN-TH-2018-076http://cds.cern.ch/record/23139532018076Dijet production in diffractive deep-inelastic scattering in next-to-next-to-leading order QCD
http://cds.cern.ch/record/2313952
Hard processes in diffractive deep-inelastic scattering can be described by a factorisation into parton-level subprocesses and diffractive parton distributions. In this framework, cross sections for inclusive dijet production in diffractive deep-inelastic electron-proton scattering (DIS) are computed to next-to-next-to-leading order (NNLO) QCD accuracy and compared to a comprehensive selection of data. Predictions for the total cross sections, 39 single-differential and four double-differential distributions for six measurements at HERA by the H1 and ZEUS collaborations are calculated. In the studied kinematical range, the NNLO corrections are found to be sizeable and positive. The NNLO predictions typically exceed the data, while the kinematical shape of the data is described better at NNLO than at next-to-leading order (NLO). A significant reduction of the scale uncertainty is achieved in comparison to NLO predictions. Our results use the currently available NLO diffractive parton distributions, and the discrepancy in normalisation highlights the need for a consistent determination of these distributions at NNLO accuracy.Britzger, D.Currie, J.Gehrmann, T.Huss, A.Niehues, J.Žlebčík, R.Wed, 18 Apr 2018 05:20:29 GMT2018-04-16CERN-TH-2018-081http://cds.cern.ch/record/23139522018081Biblioranking fundamental physics
http://cds.cern.ch/record/2313948
We propose measures of the impact of research that improve on existing ones such as counting of number of papers, citations and $h$-index. Since different papers and different fields have largely different average number of co-authors and of references we replace citations with individual citations, shared among co-authors. Next, we improve on citation counting applying the PageRank algorithm to citations among papers. Being time-ordered, this reduces to a weighted counting of citation descendants that we call PaperRank. Similarly, we compute an AuthorRank applying the PageRank algorithm to citations among authors. These metrics quantify the impact of an author or paper taking into account the impact of those authors that cite it. Finally, we show how self- and circular- citations can be eliminated by defining a closed market of citation-coins. We apply these metrics to the InSpire database that covers fundamental physics, ranking papers, authors, journals, institutes, towns, countries, continents, genders, for all-time and in recent time periods.Strumia, AlessandroTorre, RiccardoWed, 18 Apr 2018 05:19:53 GMT2018-03-28arXiv:1803.10713http://cds.cern.ch/record/2313948['arXiv:1803.10713']arXiv:1803.10713Amplitudes from superconformal Ward identities
http://cds.cern.ch/record/2312596
We consider finite superamplitudes of N=1 matter, and use superconformal symmetry to derive powerful first-order differential equations for them. Due to on-shell collinear singularities, the Ward identities have an anomaly, which is obtained from lower-loop information. We show that in the five-particle case, the solution to the equations is uniquely fixed by the expected analytic behavior. We apply the method to a non-planar two-loop five-particle integral.Chicherin, D.Henn, J.M.Sokatchev, E.Thu, 12 Apr 2018 05:49:38 GMT2018-04-10CERN-TH-2018-069http://cds.cern.ch/record/23125962018069Neutrino Masses from Outer Space
http://cds.cern.ch/record/2311940
Neutrinos can gain mass from coupling to an ultralight field in slow roll. When such a field is displaced from its minimum, its vev acts just like the Higgs vev in spontaneous symmetry breaking. Although these masses may eventually vanish, they do it over a very long time. The theory is technically natural, with the ultralight field-dependent part being the right-handed Majorana mass. The mass variation induced by the field correlates with the cosmological evolution. The change of the mass term changes the mixing matrix, and therefore suppresses the fraction of sterile neutrinos at earlier times and increases it at later times. Since the issue of quantum gravity corrections to field theories with large field variations remains open, this framework may give an observational handle on the Weak Gravity Conjecture.D'Amico, GuidoHamill, TeresaKaloper, NemanjaFri, 06 Apr 2018 05:27:32 GMT2018-04-04CERN-TH-2018-067http://cds.cern.ch/record/23119402018067Constraining Primordial Black Holes with the EDGES 21-cm Absorption Signal
http://cds.cern.ch/record/2311939
The EDGES experiment has recently measured an anomalous global 21-cm spectrum due to hydrogen absorptions at redshifts of about $z\sim 17$. Model independently, the unusually low temperature of baryons probed by this observable sets strong constraints on any physical process that transfers energy into the baryonic environment at such redshifts. Here we make use of the 21-cm spectrum to derive bounds on the energy injection due to a possible population of ${\cal O}(1-100) M_\odot$ primordial black holes, which induce a wide spectrum of radiation during the accretion of the surrounding gas. After calculating the total radiative intensity of a primordial black hole population, we estimate the amount of heat and ionisations produced in the baryonic gas and compute the resulting thermal history of the Universe with a modified version of RECFAST code. Finally, by imposing that the temperature of the gas at $z\sim 17$ does not exceed the indications of EDGES, we constrain the possible abundance of primordial black holes. Depending on uncertainties related to the accretion model, we find that ${\cal O}(10) M_\odot$ primordial black holes can only contribute to a fraction $f_{\rm PBH}<(1-10^{-2})$ of the total dark matter abundance.Hektor, AndiHütsi, GertMarzola, LucaRaidal, MarttiVaskonen, VilleVeermäe, HardiFri, 06 Apr 2018 05:27:31 GMT2018-03-26CERN-TH-2018-073http://cds.cern.ch/record/23119392018073Dark Matter Effects On Neutron Star Properties
http://cds.cern.ch/record/2311697
We study possible effects of a dark matter (DM) core on the maximum mass of a neutron star (NS), on the mass-radius relation and on the NS tidal deformability parameter $\Lambda$. We show that all these quantities would in general be reduced in the presence of a DM core. In particular, our calculations indicate that the presence of a DM core with a mass fraction $\sim 5\%$ could affect significantly the interpretation of these NS data as constraints on the nuclear equation of state (EOS), potentially excluding some EOS models on the basis of the measured mass of PSR J0348+0432, while allowing other EOS models to become consistent with the LIGO/Virgo upper limit on $\Lambda$. Specific scenarios for generating such DM cores are explored in an Appendix.Ellis, JohnHütsi, GertKannike, KristjanMarzola, LucaRaidal, MarttiVaskonen, VilleThu, 05 Apr 2018 05:24:15 GMT2018-04-04CERN-TH-2018-072http://cds.cern.ch/record/23116972018072Decoherence in neutrino propagation through matter, and bounds from IceCube/DeepCore
http://cds.cern.ch/record/2311410
We revisit neutrino oscillations in matter considering the open quantum system framework which allows to introduce possible decoherence effects generated by New Physics in a phenomenological manner. We assume that the decoherence parameters $\gamma_{ij}$ may depend on the neutrino energy, as $\gamma_{ij}=\gamma_{ij}^{0}(E/\text{GeV})^n$ $(n = 0,\pm1,\pm2) $. The case of non-uniform matter is studied in detail, both within the adiabatic approximation and in the more general non-adiabatic case. In particular, we develop a consistent formalism to study the non-adiabatic case dividing the matter profile into an arbitrary number of layers of constant densities. This formalism is then applied to explore the sensitivity of IceCube and DeepCore to this type of effects. Our study is the first atmospheric neutrino analysis where a consistent treatment of the matter effects in the three-neutrino case is performed in presence of decoherence. We show that matter effects are indeed extremely relevant in this context. We find that IceCube is able to considerably improve over current bounds in the solar sector ($\gamma_{21}$) and in the atmospheric sector ($\gamma_{31}$ and $\gamma_{32}$) for $n=0,1,2$ and, in particular, by several orders of magnitude (between 3 and 9) for the $n=1,2$ cases. For $n=0$ we find $\gamma_{32},\gamma_{31}< 4.0\cdot10^{-24} (1.3\cdot10^{-24})$ GeV and $\gamma_{21}<1.3\cdot10^{-24} (4.1\cdot10^{-24})$ GeV, for normal (inverted) mass ordering.Coloma, PilarLopez-Pavon, JacoboMartinez-Soler, IvanNunokawa, HiroshiWed, 04 Apr 2018 05:18:10 GMT2018-03-12arXiv:1803.04438http://cds.cern.ch/record/2311410['arXiv:1803.04438']arXiv:1803.04438Minimal Models for Dark Matter and the Muon g-2 Anomaly
http://cds.cern.ch/record/2311228
We construct models with minimal field content that can simultaneously explain the muon g-2 anomaly and give the correct dark matter relic abundance. These models fall into two general classes, whether or not the new fields couple to the Higgs. For the general structure of models without new Higgs couplings, we provide analytical expressions that only depend on the $SU(2)_L$ representation. These results allow to demonstrate that only few models in this class can simultaneously explain $(g-2)_\mu$ and account for the relic abundance. The experimental constraints and perturbativity considerations exclude all such models, apart from a few fine-tuned regions in the parameter space, with new states in the few 100 GeV range. In the models with new Higgs couplings, the new states can be parametrically heavier by a factor $\sqrt{1/y_\mu}$, with $y_\mu$ the muon Yukawa coupling, resulting in masses for the new states in the TeV regime. At present these models are not well constrained experimentally, which we illustrate on two representative examples.Calibbi, LorenzoZiegler, RobertZupan, JureTue, 03 Apr 2018 05:47:51 GMT2018-03-30CERN-TH-2018-068http://cds.cern.ch/record/23112282018068Dark Matter in the Standard Model?
http://cds.cern.ch/record/2310964
We critically reexamine two possible Dark Matter candidate within the Standard Model. First, we consider the $uuddss$ exa-quark. Its QCD binding energy could be large enough to make it (quasi) stable. We show that the cosmological Dark Matter abundance is reproduced thermally if its mass is 1.2 GeV. However, we also find that such mass is excluded by the stability of Oxygen nuclei. Second, we consider the possibility that the instability in the Higgs potential leads to the formation of primordial black holes while avoiding vacuum decay during inflation. We show that the non-minimal Higgs coupling to gravity must be as small as allowed by quantum corrections, $|\xi_H| < 0.01$. Even so, one must assume that the Universe survived in $e^{120}$ independent regions to fluctuations that lead to vacuum decay with probability 1/2 each.Gross, ChristianPolosa, AntonelloStrumia, AlessandroUrbano, AlfredoXue, WeiFri, 30 Mar 2018 05:32:02 GMT2018-03-27CERN-TH-2018-065http://cds.cern.ch/record/23109642018065Numerical study of the relativistic three-body quantization condition in the isotropic approximation
http://cds.cern.ch/record/2310961
We present numerical results showing how our recently proposed relativistic three-particle quantization condition can be used in practice. Using the isotropic (generalized $s$-wave) approximation, and keeping only the leading terms in the effective range expansion, we show how the quantization condition can be solved numerically in a straightforward manner. In addition, we show how the integral equations that relate the intermediate three-particle infinite-volume scattering quantity, $\mathcal K_{\text{df},3}$, to the physical scattering amplitude can be solved at and below threshold. We test our methods by reproducing known analytic results for the $1/L$ expansion of the threshold state, the volume dependence of three-particle bound-state energies, and the Bethe-Salpeter wavefunctions for these bound states. We also find that certain values of $\mathcal K_{\text{df},3}$ lead to unphysical finite-volume energies, and give a preliminary analysis of these artifacts.Briceño, Raúl A.Hansen, Maxwell T.Sharpe, Stephen R.Fri, 30 Mar 2018 05:31:45 GMT2018-03-12arXiv:1803.04169http://cds.cern.ch/record/2310961['arXiv:1803.04169']arXiv:1803.04169On Matrix Factorizations, Residue Pairings and Homological Mirror Symmetry
http://cds.cern.ch/record/2310809
We argue how boundary B-type Landau-Ginzburg models based on matrix factorizations can be used to compute exact superpotentials for intersecting D-brane configurations on compact Calabi-Yau spaces. In this paper, we consider the dependence of open-string, boundary changing correlators on bulk moduli. This determines, via mirror symmetry, non-trivial disk instanton corrections in the A-model. As crucial ingredient we propose a differential equation that involves matrix analogs of Saito's higher residue pairings. As example, we compute from this for the elliptic curve certain quantum products m_2 and m_3, which reproduce genuine boundary changing, open Gromov-Witten invariants.Lerche, WolfgangThu, 29 Mar 2018 05:21:41 GMT2018-03-27CERN-TH-2018-062http://cds.cern.ch/record/23108092018062A non-perturbative exploration of the high energy regime in $N_\text{f}=3$ QCD
http://cds.cern.ch/record/2310808
Using continuum extrapolated lattice data we trace a family of running couplings in three-flavour QCD over a large range of scales from about 4 to 128 GeV. The scale is set by the finite space time volume so that recursive finite size techniques can be applied, and Schr\"odinger functional (SF) boundary conditions enable direct simulations in the chiral limit. Compared to earlier studies we have improved on both statistical and systematic errors. Using the SF coupling to implicitly define a reference scale $1/L_0\approx 4$ GeV through $\bar{g}^2(L_0) =2.012$, we quote $L_0 \Lambda^{N_{\rm f}=3}_{\overline{\rm MS}} =0.0791(21)$. This error is dominated by statistics; in particular, the remnant perturbative uncertainty is negligible and very well controlled, by connecting to infinite renormalization scale from different scales $2^n/L_0$ for $n=0,1,\ldots,5$. An intermediate step in this connection may involve any member of a one-parameter family of SF couplings. This provides an excellent opportunity for tests of perturbation theory some of which have been published in a letter [1]. The results indicate that for our target precision of 3 per cent in $L_0 \Lambda^{N_{\rm f}=3}_{\overline{\rm MS}}$, a reliable estimate of the truncation error requires non-perturbative data for a sufficiently large range of values of $\alpha_s=\bar{g}^2/(4\pi)$. In the present work we reach this precision by studying scales that vary by a factor $2^5= 32$, reaching down to $\alpha_s\approx 0.1$. We here provide the details of our analysis and an extended discussion.Dalla Brida, MattiaFritzsch, PatrickKorzec, TomaszRamos, AlbertoSint, StefanSommer, RainerThu, 29 Mar 2018 05:21:37 GMT2018-03-27CERN-TH-2018-060http://cds.cern.ch/record/23108082018060N3LO Corrections to Jet Production in Deep Inelastic Scattering using the Projection-to-Born Method
http://cds.cern.ch/record/2310673
Computations of higher-order QCD corrections for processes with exclusive final states require a subtraction method for real-radiation contributions. We present the first-ever generalisation of a subtraction method for third-order (N3LO) QCD corrections. The Projection-to-Born method is used to combine inclusive N3LO coefficient functions with an exclusive second-order (NNLO) calculation for a final state with an extra jet. The input requirements, advantages, and potential applications of the method are discussed, and validations at lower orders are performed. As a test case, we compute the N3LO corrections to kinematical distributions and production rates for single-jet production in deep inelastic scattering in the laboratory frame, and compare them with data from the ZEUS experiment at HERA. The corrections are small in the central rapidity region, where they stabilize the predictions to sub per-cent level. The corrections increase substantially towards forward rapidity where large logarithmic effects are expected, thereby yielding an improved description of the data in this region.Currie, J.Gehrmann, T.Glover, E.W.N.Huss, A.Niehues, J.Vogt, A.Wed, 28 Mar 2018 06:08:12 GMT2018-03-27arXiv:1803.09973http://cds.cern.ch/record/2310673['arXiv:1803.09973']arXiv:1803.09973New physics searches in nuclear and neutron $\beta$ decay
http://cds.cern.ch/record/2310343
The status of tests of the standard electroweak model and of searches for new physics in allowed nuclear $\beta$ decay and neutron decay is reviewed including both theoretical and experimental developments. The sensitivity and complementarity of recent and ongoing experiments are discussed with emphasis on their potential to look for new physics. Measurements are interpreted using a model-independent effective field theory approach enabling to recast the outcome of the analysis in many specific new physics models. Special attention is given to the connection that this approach establishes with high-energy physics. A new global fit of available $\beta$-decay data is performed incorporating, for the first time in a consistent way, superallowed $0^+\to 0^+$ transitions, neutron decay and nuclear decays. The constraints on exotic scalar and tensor couplings involving left- or right-handed neutrinos are determined while a constraint on the pseudoscalar coupling from neutron decay data is obtained for the first time as well. The values of the vector and axial-vector couplings, which are associated within the standard model to $V_{ud}$ and $g_A$ respectively, are also updated. The ratio between the axial and vector couplings obtained from the fit under standard model assumptions is $C_A/C_V = -1.27510(66)$. The relevance of the various experimental inputs and error sources is critically discussed and the impact of ongoing measurements is studied. The complementarity of the obtained bounds with other low- and high-energy probes is presented including ongoing searches at the Large Hadron Collider.González-Alonso, M.Naviliat-Cuncic, O.Severijns, N.Mon, 26 Mar 2018 06:24:55 GMT2018-03-23CERN-TH-2018-050http://cds.cern.ch/record/23103432018050All rational one-loop Einstein-Yang-Mills amplitudes at four points
http://cds.cern.ch/record/2310270
All four-point mixed gluon-graviton amplitudes in pure Einstein-Yang-Mills theory with at most one state of negative helicity are computed at one-loop order and maximal powers of the gauge coupling using D-dimensional generalized unitarity. The resulting purely rational expressions take very compact forms. We comment on the color-kinematics duality picture and a relation to collinear limits of pure gluon amplitudes.Nandan, DhritimanPlefka, JanTravaglini, GabrieleSat, 24 Mar 2018 06:27:14 GMT2018-03-22HU-EP-18/04http://cds.cern.ch/record/2310270EP18/046d SCFTs and U(1) Flavour Symmetries
http://cds.cern.ch/record/2309965
We study the behaviour of abelian gauge symmetries in six-dimensional N=(1,0) theories upon decoupling gravity and investigate abelian flavour symmetries in the context of 6d N=(1,0) SCFTs. From a supergravity perspective, the anomaly cancellation mechanism implies that abelian gauge symmetries can only survive as global symmetries as gravity is decoupled. The flavour symmetries obtained in this way are shown to be free of ABJ anomalies, and their 't Hooft anomaly polynomial in the decoupling limit is obtained explicitly. In an F-theory realisation the decoupling of abelian gauge symmetries implies that a mathematical object known as the height pairing of a rational section is not contractible as a curve on the base of an elliptic Calabi-Yau threefold. We prove this prediction from supergravity by making use of the properties of the Mordell-Weil group of rational sections. In the second part of this paper we study the appearance of abelian flavour symmetries in 6d N=(1,0) SCFTs. We elucidate both the geometric origin of such flavour symmetries in F-theory and their field theoretic interpretation in terms of suitable linear combinations of geometrically massive U(1)s. Our general results are illustrated in various explicit examples.Lee, Seung-JooRegalado, DiegoWeigand, TimoThu, 22 Mar 2018 09:50:01 GMT2018-03-21CERN-TH-2018-054http://cds.cern.ch/record/23099652018054The diagrammatic coaction and the algebraic structure of cut Feynman integrals
http://cds.cern.ch/record/2308774
We present a new formula for the coaction of a large class of integrals. When applied to one-loop (cut) Feynman integrals, it can be given a diagrammatic representation purely in terms of pinches and cuts of the edges of the graph. The coaction encodes the algebraic structure of these integrals, and offers ways to extract important properties of complicated integrals from simpler functions. In particular, it gives direct access to discontinuities of Feynman integrals and facilitates a straightforward derivation of the differential equations they satisfy, which we illustrate in the case of the pentagon.Abreu, SamuelBritto, RuthDuhr, ClaudeGardi, EinanGilgen, StAustria,SpeakerAbreu, SamuelFri, 16 Mar 2018 07:03:54 GMT2018-03-15CERN-TH-2018-002http://cds.cern.ch/record/23087742018002Bounds on Dark Matter annihilations from 21 cm data
http://cds.cern.ch/record/2308097
The observation of an absorption feature in the 21 cm spectrum at redshift $z\approx 17$ implies bounds on Dark Matter annihilations for a broad range of masses, given that significant heating of the intergalactic medium would have erased such feature. The resulting bounds on the DM annihilation cross sections are comparable to the strongest ones from all other observables.D'Amico, GuidoPanci, PaoloStrumia, AlessandroMon, 12 Mar 2018 06:16:28 GMT2018-03-09CERN-TH-2018-052http://cds.cern.ch/record/23080972018052