HEP Phenomenology·hep-ph

Mon·Nov 9, 2015Monday·November 9, 2015

22 papers—14 primary·8 cross-listed·reconstructed*

01*
The Inert Zee Model
Robinson Longas🇨🇴 · Dilia Portillo🇨🇴 · Diego Restrepo🇨🇴 · Oscar Zapata🇨🇴
We study a realization of the topology of the Zee model for the generation of neutrino masses at one-loop with a minimal set of vector-like fermions. After imposing an exact $Z_{2}$ symmetry to avoid tree-level Higgs-mediated flavor changing neutral currents, one dark matter candidate is obtained from the subjacent inert doublet model, but with the presence of new co-annihilating particles. We show that the model is consistent with the constraints coming from lepton flavor violation processes, oblique parameters, dark matter and neutrino oscillation data.
hep-phJHEP(2016)·28 citations
02*
One Leptoquark to Rule Them All: A Minimal Explanation for $R_{D^{(*)}}$ , $R_{K}$ and $(g - 2)_{μ}$
Martin Bauer (U. Heidelberg)🇩🇪 · Matthias Neubert (JGU Mainz and MITP)🇩🇪
We show that by adding a single new scalar particle to the Standard Model, a TeV-scale leptoquark with the quantum numbers of a right-handed down quark, one can explain in a natural way three of the most striking anomalies of particle physics: the violation of lepton universality in $B ˉ \to K ˉ ℓ^{+} ℓ^{-}$ decays, the enhanced $B ˉ \to D^{(*)} τ ν ˉ$ decay rates, and the anomalous magnetic moment of the muon. Constraints from other precision measurements in the flavor sector can be satisfied without fine-tuning. Our model predicts enhanced $B ˉ \to K ˉ^{(*)} ν ν ˉ$ decay rates and a new-physics contribution to $B_{s} - B ˉ_{s}$ mixing close to the current central fit value.
hep-phPRL(2016)·561 citations
03*
The Higgs Mass in the MSSM at two-loop order beyond minimal flavour violation
Mark D. Goodsell🇫🇷 · Kilian Nickel🇩🇪 · Florian Staub🇨🇭
Soft supersymmetry-breaking terms provide a wealth of new potential sources of flavour violation, which are tightly constrained by precision experiments. This has posed a challenge to construct flavour models which both explain the structure of the Standard Model Yukawa couplings and also predict soft-breaking patterns that are compatible with these constraints. While such models have been studied in great detail, the impact of flavour violating soft terms on the Higgs mass at the two-loop level has been assumed to be small or negligible. In this letter, we show that large flavour violation in the up-squark sector can give a positive or negative mass shift to the SM-like Higgs of several GeV, without being in conflict with other observations. We investigate in which regions of the parameter space these effects can be expected.
hep-phPLB(2016)·17 citations
04*
Possible resolution of the domain wall problem in the NMSSM
Anupam Mazumdar🇬🇧 · Ken'ichi Saikawa🇩🇪 · Masahide Yamaguchi🇯🇵 · Jun'ichi Yokoyama🇯🇵
We discuss a possibility that the domain wall problem in the next-to-minimal supersymmetric standard model is alleviated without introducing a small explicit $Z_{3}$ breaking term by analyzing the evolution of the singlet scalar field within an inflationary paradigm. The singlet scalar field which explains the $μ$ -term tracks a time-varying minimum of the effective potential after inflation and slowly rolls down to its global minimum if there exist sufficiently large negative Hubble-induced corrections on the effective potential for the singlet field, which arise through supergravity. As a consequence, the whole Universe is confined within a single domain during and after inflation, which prevents the formation of domain walls. This will further constrain the history of the early Universe along with the Higgs-singlet coupling.
hep-phhep-thPRD(2016)·12 citations
05*
Radiatively Induced Fermi Scale in Grand Unified Theories
Tommi Alanne🇩🇰 · Aurora Meroni🇩🇰 · Francesco Sannino🇩🇰 · Kimmo Tuominen🇫🇮
We consider Grand Unified Theories in which the hierarchy between the unification and the Fermi scale emerges radiatively. Within the Pati-Salam framework, we show that it is possible to construct a viable model where the Higgs is an elementary pseudo-Goldstone boson, and the correct hierarchy is generated.
hep-phhep-thPRD(2016)·11 citations
06*
$h^{0} (125 G e V) \to c c ˉ$ as a test case for quark flavor violation in the MSSM
K. Hidaka (1)🇯🇵 · A. Bartl (2)🇦🇹 · H. Eberl (3)🇦🇹 · E. Ginina (3)🇦🇹 · W. Majerotto (3) ((1) Tokyo Gakugei U., (2) Vienna U., (3) HEPHY, Vienna)🇦🇹
We calculate the decay width of $h^{0} (125 G e V) \to c c ˉ$ in the Minimal Supersymmetric Standard Model (MSSM) with non-minimal quark flavor violation (QFV) at full one-loop level. We adopt the $DR$ renormalization scheme. We study the effects of the mixing of the second and third squark generations (i.e. scharm-stop mixing) on the decay width, respecting the experimental constraints from B-meson data, the Higgs mass measurement and supersymmetric (SUSY) particle searches. We show that the decay width $Γ (h^{0} \to c c ˉ)$ at the full one-loop level is very sensitive to the SUSY QFV parameters. In a scenario with large scharm-stop mixing, the decay width can differ up to $\sim \pm 35%$ from its SM prediction. After taking into account the experimental and theoretical uncertainties of the decay width, we conclude that these QFV SUSY effects can be observed at a future $e^{+} e^{-}$ collider such as ILC (International Linear Collider).
hep-phhep-exPoS(2015)·1 citation
07*
$η$ - $η^{'}$ mixing in large- $N_{c}$ chiral perturbation theory: discussion, phenomenology, and prospects
Patricia Bickert🇩🇪 · Pere Masjuan🇩🇪 · Stefan Scherer🇩🇪
A systematic study of the $η$ - $η^{'}$ mixing in Large- $N_{c}$ chiral perturbation theory is presented with special emphasis on the role of the next-to-next-to-leading-order contributions in the combined momentum, quark-mass, and $1/ N_{c}$ expansions. At this order, loop corrections as well as OZI-rule-violating pieces need to be included. Mixing angles as well as pseudoscalar decay constants are discussed within this framework. The results are compared with recent phenomenological approaches.
hep-phhep-latnucl-thPoS(2016)·3 citations
08*
Off-trail SUSY
Karim Benakli🇫🇷 · Luc Darmé🇫🇷
We present two distinct topics: I) We describe the propagation of a spin-3/2 state in a background which preserves invariance under space translations and rotations but not under Lorentz boost transformations. We start by building a generalisation of the Volkov-Akulov Lagrangian for a goldstino in a fluid. A super-Higgs mechanism leads to the modified Rarita-Schwinger Lagrangian describing a slow gravitino. We identify the physical propagating degrees of freedom and derive the corresponding equations of motion. This includes some new results. II) Fake Split Supersymmetry Models are proposed to alleviate some of the problems of the original Split SUSY. In particular it is no more necessary to restrict to a Mini-Split scenario as higher values of the supersymmetry breaking scale (Mega-Split) are now allowed. The FSSM relies on swapping the higgsinos for new states in identical gauge group representations but different Yukawa couplings.
hep-phhep-thPoS(2015)·2 citations
09*
Four-lepton production from photon-induced reactions in $pp$ collisions at the LHC
Mateusz Dyndal (AGH Univ. of Science and Technology and DESY)🇵🇱 · Laurent Schoeffel (CEA Saclay, Irfu/SPP)🇫🇷
The cross sections for the reaction $γ γ \to 4 ℓ$ in proton--proton collisions are calculated at the LHC energies. We show that the purely electroweak process $γ γ \to 4 ℓ$ can be studied at the LHC and can constitute a background to other processes with $4 ℓ$ or $2 ℓ$ final states.
hep-phActa Phys.Polon.B(2016)·7 citations
10*
Gauge coupling unification in a classically scale invariant model
Naoyuki Haba🇯🇵 · Hiroyuki Ishida🇯🇵 · Ryo Takahashi🇯🇵 · Yuya Yamaguchi🇯🇵
There are a lot of works within a class of classically scale invariant model, which is motivated by solving the gauge hierarchy problem. In this context, the Higgs mass vanishes at the UV scale due to the classically scale invariance, and is generated via the Coleman-Weinberg mechanism. Since the mass generation should occur not so far from the electroweak scale, we extend the standard model only around the TeV scale. We construct a model which can achieve the gauge coupling unification at the UV scale. In the same way, the model can realize the vacuum stability, smallness of active neutrino masses, baryon asymmetry of the universe, and dark matter relic abundance. The model predicts the existence vector-like fermions charged under $S U (3)_{C}$ with masses lower than $1 TeV$ , and the SM singlet Majorana dark matter with mass lower than $2.6 TeV$ .
hep-phJHEP(2016)·23 citations
11*
Quark-Lepton Complementarity Predictions for $θ_{23}^{p mn s}$ and CP Violation
Gazal Sharma🇮🇳 · B. C. Chauhan🇮🇳
In the light of recent experimental results on $θ_{13}^{p mn s}$ , we re-investigate the complementarity between the quark and lepton mixing matrices and obtain predictions for most unsettled neutrino mixing parameters like $θ_{23}^{p mn s}$ and CP violating phase invariants $J$ , $S_{1}$ and $S_{2}$ . This paper is motivated by our previous work where in a QLC model we predicted the value for $θ_{13}^{p mn s} = (9_{- 2}^{+ 1})^{\circ}$ , which was found to be in strong agreement with the experimental results. In the QLC model the non-trivial correlation between CKM and PMNS mixing matrices is given by a correlation matrix ( $V_{c}$ ). We do numerical simulation and estimate the texture of the $V_{c}$ and in our findings we get a small deviation from the Tri-Bi-Maximal (TBM) texture and a large from the Bi-Maximal one, which is consistent with the work already reported in literature. In the further investigation we obtain quite constrained limits for $s i n^{2} θ_{23}^{p mn s} = 0.423 5_{- 0.0043}^{+ 0.0032}$ that is narrower to the existing ones. We also obtain the constrained limits for the three CP violating phase invariants $J$ , $S_{1}$ and $S_{2}$ : as $J < 0.0315$ , $S_{1} < 0.12$ and $S_{2} < 0.08$ , respectively.
hep-phJHEP(2016)·9 citations
12*
Signals of a 2 TeV $W^{'}$ boson and a heavier $Z^{'}$ boson
Bogdan A. Dobrescu🇺🇸 · Patrick J. Fox🇺🇸
We construct an $S U (2)_{L} \times S U (2)_{R} \times U (1)_{B - L}$ model with a Higgs sector that consists of a bidoublet and a doublet, and with a right-handed neutrino sector that includes one Dirac fermion and one Majorana fermion. This model explains the Run 1 CMS and ATLAS excess events in the $e^{+} e^{-} j j$ , $j j$ , $W h^{0}$ and $W Z$ channels in terms of a $W^{'}$ boson of mass near 1.9 TeV and of coupling $g_{R}$ in the 0.4--0.5 range, with the lower half preferred by limits on $t b ˉ$ resonances and Run 2 results. The production cross section of this $W^{'}$ boson at the 13 TeV LHC is in the 700--900 fb range, allowing sensitivity in more than 17 final states. We determine that the $Z^{'}$ boson has a mass in the 3.4--4.5 TeV range and several decay channels that can be probed in Run 2 of the LHC, including cascade decays via heavy Higgs bosons.
hep-phJHEP(2016)·44 citations
13*
Production of a forward J/psi and a backward jet at the LHC
R. Boussarie🇫🇷 · B. Ducloué🇫🇮 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷
We study the production of a forward $J / ψ$ meson and a backward jet with a large rapidity separation at the LHC using the BFKL formalism. We compare the predictions given by the Non Relativistic QCD (NRQCD) approach to charmonium prediction and by the Color Evaporation Model. In NRQCD, we find that the $^{3} S_{1}^{8}$ part of the onium wavefunction is completely dominating the process. NRQCD and the color evaporation model give similar results, although a discrepancy seems to appear as the value of the transverse momenta of the charmonium and of the jet decrease.
hep-ph8 citations
14*
A Classical Solution of Massive Yang-Mills Fields
Tsuguo Mogami🇯🇵
Recent researches on the solution of Schwinger-Dyson equations, as well as lattice simulations of pure QCD, suggest that the gluon propagator is massive. In this letter, we assume that the classical counterpart of this massive gluon field may be represented with the equation of motion for Yang-Mills theory with a mass term added. A new classical solution is given for this equation. It is discussed that this solution may have some role in confinement.
hep-ph0 citations
15*
Discrete Flavour Symmetries from the Heisenberg Group
E.G. Floratos🇨🇭 · G.K. Leontaris🇬🇷
Non-abelian discrete symmetries are of particular importance in model building. They are mainly invoked to explain the various fermion mass hierarchies and forbid dangerous superpotential terms. In string models they are usually associated to the geometry of the compactification manifold and more particularly to the magnetised branes in toroidal compactifications. Motivated by these facts, in this note we propose a unified framework to construct representations of finite discrete family groups based on the automorphisms of the discrete and finite Heisenberg group. We focus in particular in the $P S L_{2} (p)$ groups which contain the phenomenologically interesting cases.
↳ hep-thhep-phmath-phmath.MPPLB(2016)·3 citations
16*
Towards a Theory of the QCD String
Sergei Dubovsky🇺🇸 · Victor Gorbenko🇺🇸
We construct a new model of four-dimensional relativistic strings with integrable dynamics on the worldsheet. In addition to translational modes this model contains a single massless pseudoscalar worldsheet field - the worldsheet axion. The axion couples to a topological density which counts the self-intersection number of a string. The corresponding coupling is fixed by integrability to $Q = \frac{7}{16 π} \approx 0.37$ . We argue that this model is a member of a larger family of relativistic non-critical integrable string models. This family includes and extends conventional non-critical strings described by the linear dilaton CFT. Intriguingly, recent lattice data in $S U (3)$ and $S U (5)$ gluodynamics reveals the presence of a massive pseudoscalar axion on the worldsheet of confining flux tubes. The value of the corresponding coupling, as determined from the lattice data, is equal to $Q_{L} \approx 0.38 \pm 0.04$ .
↳ hep-thhep-lathep-phJHEP(2016)·68 citations
17*
The Low Energy Constants of $S U (2)$ Partially Quenched Chiral Perturbation Theory from $N_{f} = 2 + 1$ Domain Wall QCD
P.A. Boyle🇬🇧 · N.H. Christ🇺🇸 · N. Garron🇬🇧 · C. Jung🇺🇸 · A. Jüttner🇬🇧 · C. Kelly🇺🇸 · R.D. Mawhinney🇺🇸 · G. McGlynn🇺🇸 · D.J. Murphy🇺🇸 · S. Ohta🇯🇵 · A. Portelli🇬🇧 · C.T. Sachrajda🇬🇧
We have performed fits of the pseudoscalar masses and decay constants, from a variety of RBC-UKQCD domain wall fermion ensembles, to $S U (2)$ partially quenched chiral perturbation theory at next-to leading order (NLO) and next-to-next-to leading order (NNLO). We report values for 9 NLO and 8 linearly independent combinations of NNLO partially quenched low energy constants, which we compare to other lattice and phenomenological determinations. We discuss the size of successive terms in the chiral expansion and use our large set of low energy constants to make predictions for mass splittings due to QCD isospin breaking effects and the S-wave $π π$ scattering lengths. We conclude that, for the range of pseudoscalar masses explored in this work, $115 MeV ≲ m_{PS} ≲ 430 MeV$ , the NNLO $S U (2)$ expansion is quite robust and can fit lattice data with percent-scale accuracy.
↳ hep-lathep-phPRD(2016)·98 citations
18*
Nucleon Polarisabilities at and Beyond Physical Pion Masses
Harald W. Griesshammer (George Washington U.)🇺🇸 · Judith A. McGovern (U. of Manchester)🇬🇧 · Daniel R. Phillips (Ohio U.)🇺🇸
We examine the results of Chiral Effective Field Theory ( $χ$ EFT) for the scalar- and spin-dipole polarisabilities of the proton and neutron, both for the physical pion mass and as a function of $m_{π}$ . This provides chiral extrapolations for lattice-QCD polarisability computations. We include both the leading and sub-leading effects of the nucleon's pion cloud, as well as the leading ones of the $Δ (1232)$ resonance and its pion cloud. The analytic results are complete at N $^{2}$ LO in the $δ$ -counting for pion masses close to the physical value, and at leading order for pion masses similar to the Delta-nucleon mass splitting. In order to quantify the truncation error of our predictions and fits as $68$ \% degree-of-belief intervals, we use a Bayesian procedure recently adapted to EFT expansions. At the physical point, our predictions for the spin polarisabilities are, within respective errors, in good agreement with alternative extractions using experiments and dispersion-relation theory. At larger pion masses we find that the chiral expansion of all polarisabilities becomes intrinsically unreliable as $m_{π}$ approaches about $300$ MeV---as has already been seen in other observables. $χ$ EFT also predicts a substantial isospin splitting above the physical point for both the electric and magnetic scalar polarisabilities; and we speculate on the impact this has on the stability of nucleons. Our results agree very well with emerging lattice computations in the realm where $χ$ EFT converges. Curiously, for the central values of some of our predictions, this agreement persists to much higher pion masses. We speculate on whether this might be more than a fortuitous coincidence.
↳ nucl-thhep-lathep-phEPJA(2016)·53 citations
19*
Lattice study for conformal windows of SU(2) and SU(3) gauge theories with fundamental fermions
Cynthia Y.-H. Huang🇹🇼 · Issaku Kanamori🇯🇵 · C.-J. David Lin🇹🇼 · Kenji Ogawa🇹🇼 · Hiroshi Ohki🇺🇸 · Alberto Ramos🇨🇭 · Enrico Rinaldi🇺🇸
We present our investigation of SU(2) gauge theory with 8 flavours, and SU(3) gauge theory with 12 flavours. For the SU(2) case, at strong bare coupling, $β ≲ 1.45$ , the distribution of the lowest eigenvalue of the Dirac operator can be described by chiral random matrix theory for the Gaussian symplectic ensemble. Our preliminary result indicates that the chiral phase transition in this theory is of bulk nature. For the SU(3) theory, we use high-precision lattice data to perform the step-scaling study of the coupling, $g_{GF}$ , in the Gradient Flow scheme. We carefully examine the reliability of the continuum extrapolation in the analysis, and conclude that the scaling behaviour of this SU(3) theory is not governed by possible infrared conformality at $g_{GF}^{2} ≲ 6$ .
↳ hep-lathep-phPoS(2016)·4 citations
20*
Hagedorn transition and topological entanglement entropy
Fen Zuo🇨🇳 · Yi-Hong Gao🇨🇳
Induced by the Hagedorn instability, weakly-coupled $U (N)$ gauge theories on a compact manifold exhibit a confinement/deconfinement phase transition in the large- $N$ limit. Recently we discover that the thermal entropy of a free theory on $S^{3}$ gets reduced by a universal constant term, $- N^{2} /4$ , compared to that from completely deconfined colored states. This entropy deficit is due to the persistence of Gauss's law, and actually independent of the shape of the manifold. In this paper we show that this universal term can be identified as the topological entangle entropy both in the corresponding $4 + 1 D$ bulk theory and the dimensionally reduced theory. First, entanglement entropy in the bulk theory contains the so-called "particle" contribution on the entangling surface, which naturally gives rise to an area-law term. The topological term results from the Gauss's constraint of these surface states. Secondly, the high-temperature limit also defines a dimensionally reduced theory. We calculate the geometric entropy in the reduced theory explicitly, and find that it is given by the same constant term after subtracting the leading term of $O (β^{- 1})$ . The two procedures are then applied to the confining phase, by extending the temperature to the complex plane. Generalizing the recently proposed $2 D$ modular description to an arbitrary matter content, we show the leading local term is missing and no topological term could be definitely isolated. For the special case of $N = 4$ super Yang-Mills theory, the results obtained here are compared with that at strong coupling from the holographic derivation.
↳ hep-thhep-lathep-phNPB(2016)·4 citations
21*
Status of Indirect (and Direct) Dark Matter searches
Marco Cirelli🇫🇷
This article summarizes the status of Indirect and Direct searches for Dark Matter, with a special focus and a critical look on the former. It is the write-up of a rapporteur talk given at the 34th International Cosmic Ray Conference (ICRC 2015) in The Hague, The Netherlands.
↳ astro-ph.HEhep-phPoS(2016)·46 citations
22*
Heavy-ion collisions at the Large Hadron Collider: a review of the results from Run 1
N. Armesto🇪🇸 · E. Scomparin🇮🇹
We present an overview of the results obtained in pPb and PbPb collisions at the Large Hadron Collider during Run 1. We first discuss the results for global characteristics: cross sections, hadron multiplicities, azimuthal asymmetries, correlations at low transverse momentum, hadrochemistry, and femtoscopy. We then review hard and electromagnetic probes: particles with high transverse momentum, jets, heavy quarks, quarkonium, electroweak bosons and high transverse momentum photons, low transverse momentum photons and dileptons, and ultraperipheral collisions. We mainly focus on the experimental results, and present very briefly the main current theoretical explanations.
↳ nucl-exhep-exhep-phnucl-thEur.Phys.J.Plus(2016)·97 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.