HEP Phenomenology·hep-ph

Wed·Apr 11, 2018Wednesday·April 11, 2018

21 papers—13 primary·8 cross-listed·reconstructed*

01*
Seesaw Dirac neutrino mass through dimension-6 operators
Salvador Centelles Chuliá🇪🇸 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸
In this paper, a followup of arXiv: 1802.05722, we describe the many pathways to generate Dirac neutrino mass through dimension-6 operators. By using only the Standard Model Higgs doublet in the external legs one gets a unique operator $\frac{1}{Λ ^{2}} L ˉ Φ ˉ Φ ˉ Φ ν_{R}$ . In contrast, the presence of new scalars implies new possible field contractions, which greatly increase the number of possibilities. Here we study in detail the simplest ones, involving $S U (2)_{L}$ singlets, doublets and triplets. The extra symmetries needed to ensure the Dirac nature of neutrinos can also be responsible for stabilizing dark matter.
hep-phPRD(2018)·67 citations
02*
Rare Radiative Decays of Vector and Axial-Vector $B_{c}$ Mesons to $(D_{s}, D_{s}^{*}, D_{s 1})$ Final States
A. R. Olamaei🇮🇷
In this work, we use the QCD sum rule method to study the radiative decays of the vector and axial-vector $B_{c}$ mesons to each of three charmed strange mesons, $D_{s}$ , $D_{s}^{*}$ and $D_{s 1}$ , through their dominant weak annihilation channels. We calculate all relevant transition form factors, which are used to estimate the branching fractions at different channels. The order of branching ratios are obtained to be in the order of $1 0^{- 6} - 1 0^{- 5}$ , which may be checked via differnet experiments.
hep-phEur.Phys.J.Plus(2018)·1 citation
03*
Exclusive vector meson production with leading neutrons in a saturation model for the dipole amplitude in mixed space
J. T. Amaral🇧🇷 · V. M. Becker🇧🇷
We investigate $ρ$ vector meson production in $e p$ collisions at HERA with leading neutrons in the dipole formalism. The interaction of the dipole and the pion is described in a mixed-space approach, in which the dipole-pion scattering amplitude is given by the Marquet-Peschanski-Soyez saturation model, which is based on the travelling wave solutions of the nonlinear Balitsky-Kovchegov equation. We estimate the magnitude of the absorption effects and compare our results with a previous analysis of the same process in full coordinate space. In contrast with this approach, the present study leads to absorption $K$ factors in the range of those predicted by previous theoretical studies on semi-inclusive processes.
hep-phPRD(2018)·4 citations
04*
The Effect of a Light Sterile Neutrino at NO $ν$ A and DUNE
Shivani Gupta🇦🇺 · Zachary M. Matthews🇦🇺 · Pankaj Sharma🇦🇺 · Anthony G. Williams🇦🇺
Now that the NOvA experiment is approaching two years run time and has released some preliminary data, some constraints for the oscillation parameters can be inferred. Currently the best fits for NOvA are three separate results, the reason they are indistinct is that they produce almost degenerate probability curves. It has been postulated that these degeneracies can be resolved by running antineutrinos at NOvA and/or combining its data with T2K. However, this degeneracy resolution power can be compromised if sterile neutrinos are present due to additional degrees of freedom that can significantly alter the oscillation probability for any of the current best fits. We aim to investigate this degradation in predictive power and the effect of the DUNE experiment on it. Now that the NOvA experiment has been running for a few years and has released some preliminary data, some constraints for the oscillation parameters can be inferred. The best fits for NOvA include three degenerate results, the reason they are indistinct is that they produce almost degenerate probability curves. It has been postulated that these degeneracies can be resolved by running antineutrinos at NOvA and/or combining its data with T2K. However, this degeneracy resolution power can be compromised if sterile neutrinos are present due to additional degrees of freedom that can significantly alter the oscillation probability for any of these best fits. We aim to investigate this degradation in predictive power and the effect of the DUNE experiment on it. In light of the 2018 NOvA data we also consider the same fits but with theta_{23}=45 to see if the sensitivity results are different.
hep-phPRD(2018)·25 citations
05*
A singlet doublet dark matter model with radiative neutrino masses
S. Esch🇩🇪 · M. Klasen🇩🇪 · C. Yaguna🇨🇴
We present a detailed study of a combined singlet-doublet scalar and singlet-doublet fermion model for dark matter. These models have only been studied separately in the past. We show that their combination allows for the radiative generation of neutrino masses, but that it also implies the existence of lepton-flavour violating (LFV) processes. We first analyse the dark matter, neutrino mass and LFV aspects separately. We then perform two random scans for scalar dark matter imposing Higgs mass, relic density and neutrino mass constraints, one over the full parameter space, the other over regions where scalar-fermion coannihilations become important. In the first case, a large part of the new parameter space is excluded by LFV, and the remaining models will be probed by XENONnT. In the second case, direct detection cross sections are generally too small, but a substantial part of the viable models will be tested by future LFV experiments. Possible constraints from the LHC are also discussed.
hep-phJHEP(2018)·35 citations
06*
Reheating neutron stars with the annihilation of self-interacting dark matter
Chian-Shu Chen🇹🇼 · Yen-Hsun Lin🇹🇼
Compact stellar objects such as neutron stars (NS) are ideal places for capturing dark matter (DM) particles. We study the effect of self-interacting DM (SIDM) captured by nearby NS that can reheat it to an appreciated surface temperature through absorbing the energy released due to DM annihilation. When DM-nucleon cross section $σ_{χ n}$ is small enough, DM self-interaction will take over the capture process and make the number of captured DM particles increased as well as the DM annihilation rate. The corresponding NS surface temperature resulted from DM self-interaction is about hundreds of Kelvin and is potentially detectable by the future infrared telescopes. Such observations could act as the complementary probe on DM properties to the current DM direct searches.
hep-phJHEP(2018)·66 citations
07*
Dilepton photoproduction on a deuteron target
Carl E. Carlson (William and Mary)🇺🇸 · Vladyslav Pauk🇩🇪 · Marc Vanderhaeghen (Johannes Gutenberg-University, Mainz)🇩🇪
We investigate the sensitivity of the cross section for lepton pair production off a deuteron target, $γ d \to l^{+} l^{-} d$ , to the deuteron charge radius. We show that for small momentum transfers the Bethe-Heitler process dominates, and that it is sensitive to the charge radius such that a cross section ratio measurement of about $0.1%$ relative accuracy could give a deuteron charge radius more accurate that the current electron scattering value and sufficiently accurate to distinguish between the electronic and muonic atomic values.
hep-phnucl-thPLB(2019)·5 citations
08*
Revisiting the D-meson hadroproduction in general-mass variable flavour number scheme
Ilkka Helenius🇩🇪 · Hannu Paukkunen🇫🇮
We introduce a novel realization of the open heavy-flavour hadroproduction in general-mass variable flavour number scheme at next-to-leading order in perturbative QCD. The principal novelty with respect to the earlier works is in the treatment of small-transverse-momentum limit, which has been a particularly challenging kinematic region in the past. We show that by a suitable choice of scheme, it is possible to obtain a well-behaved description of the open heavy-flavour hadroproduction cross sections from zero up to asymptotically high transverse momentum. We contrast our calculation with the available D $^{0}$ -meson data as measured by the LHCb and ALICE collaborations at the LHC, finding a very good agreement within the theoretical and experimental uncertainties. We also compare our framework with other theoretical approaches.
hep-phhep-exJHEP(2018)·114 citations
09*
Dark Photons, Kinetic Mixing and Light Dark Matter From 5-D
Thomas G. Rizzo🇺🇸
Extra dimensions provide a unique tool for building new physics models. Here we extend the kinetic mixing/dark photon mediator scenario for the case of complex scalar dark matter interacting with the Standard Model to 5-D. We assume that the inverse size of the new, flat extra dimension is $\sim 10 - 1000$ MeV, the mass range of interest in numerous current experiments, and discuss the resulting phenomenology. Here we see that 5-D constructions can be used to soften some of the possible tuning issues which are sometimes encountered in the corresponding 4-D models.
hep-ph5 citations
10*
On the model dependence of measured Bs-meson branching fractions
Francesco Dettori🇬🇧 · Diego Guadagnoli🇫🇷
The measurement of $B_{s}$ -meson branching fractions is a fundamental tool to probe physics beyond the Standard Model. Every measurement of untagged time-integrated $B_{s}$ -meson branching fractions is model-dependent due to the time dependence of the experimental efficiency and the large lifetime difference between the two $B_{s}$ mass eigenstates. In recent measurements, this effect is bundled in the systematics. We reappraise the potential numerical impact of this effect -- we find it to be close to 10% in real-life examples where new physics is a correction to dominantly Standard-Model dynamics. We therefore suggest that this model dependence be made explicit, i.e. that $B_{s}$ branching-fraction measurements be presented in a two-dimensional plane with the parameter that encodes the model dependence. We show that ignoring this effect can lead to over-constraining the couplings of new-physics models. In particular, we note that the effect also applies when setting upper limits on non-observed $B_{s}$ decay modes, such as those forbidden within the Standard Model.
hep-phhep-exPLB(2018)·6 citations
11*
Recursive Soft Drop
Frédéric A. Dreyer🇺🇸 · Lina Necib🇺🇸 · Gregory Soyez🇫🇷 · Jesse Thaler🇺🇸
We introduce a new jet substructure technique called Recursive Soft Drop, which generalizes the Soft Drop algorithm to have multiple grooming layers. Like the original Soft Drop method, this new recursive variant traverses a jet clustering tree to remove soft wide-angle contamination. By enforcing the Soft Drop condition N times, Recursive Soft Drop improves the jet mass resolution for boosted hadronic objects like W bosons, top quarks, and Higgs bosons. We further show that this improvement in mass resolution persists when including the effects of pileup, up to large pileup multiplicities. In the limit that N goes to infinity, the resulting groomed jets formally have zero catchment area. As an alternative approach, we present a bottom-up version of Recursive Soft Drop which, in its local form, is similar to Recursive Soft Drop and which, in its global form, can be used to perform event-wide grooming.
hep-phhep-exJHEP(2018)·69 citations
12*
A Plan to Rule out Large Non-Standard Neutrino Interactions After COHERENT Data
Peter B. Denton🇩🇰 · Yasaman Farzan🇮🇷 · Ian M. Shoemaker🇺🇸
In the presence of neutrino Non-Standard Interactions (NSI) with matter, the derivation of neutrino parameters from oscillation data must be reconsidered. In particular, along with the standard solution to neutrino oscillation, another solution known as "LMA--Dark" is compatible with global oscillation data and requires both $θ_{12} > π /4$ and a certain flavor pattern of NSI with an effective coupling comparable to $G_{F}$ . Contrary to conventional expectations, there is a class of models based on a new $U (1)_{X}$ gauge symmetry with a gauge boson of mass of few MeV to few 10 MeV that can viably give rise to such large NSI. These models can in principle be tested by Coherent Elastic $ν$ -Nucleus Scattering (CE $ν$ NS) experiments such as COHERENT and the upcoming reactor neutrino experiment, CONUS. We analyze how the recent results from the COHERENT experiment constrain these models and forecast the discovery potential with future measurements from COHERENT and CONUS. We also derive the constraints from COHERENT on lepton flavor violating NSI.
hep-phhep-exJHEP(2018)·198 citations
13*
The Flavor of Cosmology
Benjamin Lillard🇺🇸 · Michael Ratz🇺🇸 · Tim M.P. Tait🇺🇸 · Sebastian Trojanowski🇺🇸
We discuss the cosmology of models in which the standard model Yukawa couplings depend on scalar field(s), often referred to as flavons. We find that thermal corrections of the flavon potential tend to decrease the Yukawa couplings, providing an important input to model-building. Working in the specific framework of Froggatt-Nielsen models, we compute the abundance of flavons in the early universe generated both via freeze-in and from coherent oscillations induced by thermal corrections to their potential, and discuss constraints on flavon models from cosmology. We find that cosmology places important constraints on theories containing flavons even for regions of parameter space inaccessible to collider searches.
hep-phastro-ph.COhep-thJCAP(2018)·24 citations
14*
Critical chiral hypersurface of the magnetized NJL model
Angelo Martínez🇲🇽 · Alfredo Raya🇲🇽
In pursuit of the sketching the effective magnetized QCD phase diagram, we found conditions on the critical coupling for chiral symmetry breaking in the Nambu-Jona-Lasinio model in a nontrivial thermo-magnetic environment. Critical values for the plasma parameters, namely, temperature and magnetic field strength for this to happen are hence found in the mean field limit. The magnetized phase diagram is drawn from the criticality condition for different models of the effective coupling describing the inverse magnetic catalysis effect.
↳ hep-thhep-phNPB(2018)·10 citations
15*
Probing Ultralight Bosons with Binary Black Holes
Daniel Baumann🇳🇱 · Horng Sheng Chia🇳🇱 · Rafael A. Porto🇧🇷
We study the gravitational-wave (GW) signatures of clouds of ultralight bosons around black holes (BHs) in binary inspirals. These clouds, which are formed via superradiance instabilities for rapidly rotating BHs, produce distinct effects in the population of BH masses and spins, and a continuous monochromatic GW signal. We show that the presence of a binary companion greatly enriches the dynamical evolution of the system, most remarkably through the existence of resonant transitions between the growing and decaying modes of the cloud (analogous to Rabi oscillations in atomic physics). These resonances have rich phenomenological implications for current and future GW detectors. Notably, the amplitude of the GW signal from the clouds may be reduced, and in many cases terminated, much before the binary merger. The presence of a boson cloud can also be revealed in the GW signal from the binary through the imprint of finite-size effects, such as spin-induced multipole moments and tidal Love numbers. The time dependence of the cloud's energy density during the resonance leads to a sharp feature, or at least attenuation, in the contribution from the finite-size terms to the waveforms. The observation of these effects would constrain the properties of putative ultralight bosons through precision GW data, offering new probes of physics beyond the Standard Model.
↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1PRD(2019)·370 citations
16*
Neutrino Cross Sections: Status and Prospects
M. F. Carneiro🇺🇸
We summarize the current status of accelerator based neutrino crosssection measurements. We focus on the experimental challenges while also presenting the motivation for these measurements. Selected results are highlighted after a quick description of the current major collaborations working on the field.
↳ hep-exhep-ph1 citation
17*
A narrow band neutrino beam with high precision flux measurements
A. Coffani · G. Ballerini · A. Berra🇮🇹 · R. Boanta · M. Bonesini🇮🇹 · C. Brizzolari · G. Brunetti · M. Calviani🇨🇭 · S. Carturan · M. G. Catanesi🇮🇹 · S. Cecchini🇮🇹 · F. Cindolo🇮🇹 and 40 other authors
The ENUBET facility is a proposed narrow band neutrino beam where lepton production is monitored at single particle level in the instrumented decay tunnel. This facility addresses simultaneously the two most important challenges for the next generation of cross section experiments: a superior control of the flux and flavor composition at source and a high level of tunability and precision in the selection of the energy of the outcoming neutrinos. We report here the latest results in the development and test of the instrumentation for the decay tunnel. Special emphasis is given to irradiation tests of the photo-sensors performed at INFN-LNL and CERN in 2017 and to the first application of polysiloxane-based scintillators in high energy physics.
↳ physics.ins-dethep-exhep-ph0 citations
18*
Meson-exchange currents and quasielastic predictions for neutrino-nucleus scattering
M.B. Barbaro🇮🇹 · J.E. Amaro🇪🇸 · J.A. Caballero🇪🇸 · A. De Pace🇮🇹 · T.W. Donnelly🇺🇸 · G.D. Megias🇪🇸 · I. Ruiz Simo🇪🇸
We review some recent progress in the study of electroweak interactions in nuclei within the SuSAv2-MEC model. The model has the capability to predict (anti)neutrino scattering observables on different nuclei. The theoretical predictions are compared with the recent T2K $ν_{μ} -^{16}$ O data and good agreement is found at all kinematics. The results are very similar to those obtained for $ν_{μ} -^{12}$ C scattering, except at low energies, where some differences emerge. The role of meson-exchange currents in the two-particle two-hole channel is analyzed in some detail. In particular it is shown that the density dependence of these contributions is different from what is found for the quasielastic response.
↳ nucl-thhep-phnucl-exPoS(2017)·0 citations
19*
Heavy-quark dynamics in a hydrodynamically evolving medium
Marlene Nahrgang🇫🇷 · Joerg Aichelin🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Klaus Werner (SUBATECH, Nantes)🇫🇷
In this talk we will discuss the recent advances in describing heavy-quark dynamics in the quark-gluon plasma (QGP), which evolves hydrodynamically. Special emphasis is put on the collective flow of the heavy-quarks with the medium constituents, for which we present our latest results obtained within the MC@sHQ+EPOS2 model at $s = 5$ ~TeV.
↳ nucl-thhep-phEPJ Web Conf.(2018)·2 citations
20*
Amplitudes from superconformal Ward identities
Dmitry Chicherin🇩🇪 · Johannes M. Henn🇩🇪 · Emery Sokatchev🇩🇪
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.
↳ hep-thhep-phPRL(2018)·28 citations
21*
Cosmological singularities and analytical solutions in varying vacuum cosmologies
S. Basilakos🇬🇷 · A. Paliathanasis🇨🇱 · J.D. Barrow🇬🇧 · G. Papagiannopoulos🇬🇷
We investigate the dynamical features of a large family of running vacuum cosmologies for which $Λ$ evolves as a polynomial in the Hubble parameter. Specifically, using the critical point analysis we study the existence and the stability of singular solutions which describe de-Sitter, radiation and matter dominated eras. We find several classes of $Λ (H)$ cosmologies for which new analytical solutions are given in terms of Laurent expansions. Finally, we show that the Milne universe and the $R_{h} = c t$ model can be seen as perturbations around a specific $Λ (H)$ model, but this model is unstable.
↳ gr-qchep-phEPJC(2018)·19 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.