HEP Phenomenology·hep-ph
15 papers—12 primary·3 cross-listed·reconstructed*
We develop an approach based on the light-cone sum rules at the leading order of to calculate the gravitational form factors and for the valence quark combinations in nucleon. Within the proposed model, the predictions for the gravitational form factor (-term contributions) have been presented. Comparison with the experimental data and with the results of different models is discussed.
T. Csörgő🇭🇺 · R. Pasechnik🇸🇪 · A. Ster🇭🇺
A novel model-independent Lévy imaging method is employed for reconstruction of the elastic and scattering amplitudes at low and high energies. The four-momentum transfer dependent elastic slope , the nuclear phase as well as the excitation function of the shadow profile have been extracted from data at ISR, Tevatron and LHC energies. We found qualitative differences in properties of and between and for collisions, that indicate an Odderon effect. A proton substructure has also been identified and found to have two different sizes, comparable to that of a dressed quark at the ISR and of a dressed diquark at the LHC energies, respectively.
Ariel Arza🇺🇸 · Pierre Sikivie🇺🇸
Electromagnetic radiation with angular frequency equal to half the axion mass stimulates the decay of cold dark matter axions and produces an echo, i.e. faint electromagnetic radiation traveling in the opposite direction. We propose to search for axion dark matter by sending out to space a powerful beam of microwave radiation and listening for its echo. We estimate the sensitivity of this technique in the isothermal and caustic ring models of the Milky Way halo, and find it to be a promising approach to axion, or axion-like, dark matter detection.
M. Cepeda · S. Gori · P. Ilten · M. Kado · F. Riva · R. Abdul Khalek · A. Aboubrahim · J. Alimena · S. Alioli · A. Alves · C. Asawatangtrakuldee · A. Azatov and 365 other authors
The discovery of the Higgs boson in 2012, by the ATLAS and CMS experiments, was a success achieved with only a percent of the entire dataset foreseen for the LHC. It opened a landscape of possibilities in the study of Higgs boson properties, Electroweak Symmetry breaking and the Standard Model in general, as well as new avenues in probing new physics beyond the Standard Model. Six years after the discovery, with a conspicuously larger dataset collected during LHC Run 2 at a 13 TeV centre-of-mass energy, the theory and experimental particle physics communities have started a meticulous exploration of the potential for precision measurements of its properties. This includes studies of Higgs boson production and decays processes, the search for rare decays and production modes, high energy observables, and searches for an extended electroweak symmetry breaking sector. This report summarises the potential reach and opportunities in Higgs physics during the High Luminosity phase of the LHC, with an expected dataset of pp collisions at 14 TeV, corresponding to an integrated luminosity of 3 ab. These studies are performed in light of the most recent analyses from LHC collaborations and the latest theoretical developments. The potential of an LHC upgrade, colliding protons at a centre-of-mass energy of 27 TeV and producing a dataset corresponding to an integrated luminosity of 15 ab, is also discussed.
Chandrasekhar Chatterjee🇯🇵 · Muneto Nitta.🇯🇵 · Shigehiro Yasui🇯🇵
The quark-hadron crossover conjecture was proposed as a continuity between hadronic matter and quark matter with no phase transition. It is based on matching of symmetry and excitations in both the phases. It connects hyperon matter and color-flavor locked (CFL) phase of color superconductivity in the limit of light strange quark mass. We study generalization of this conjecture in the presence of topological vortices. We propose a picture where hadronic superfluid vortices in hyperon matter could be connected to non-Abelian vortices (color magnetic flux tubes) in the CFL phase during this crossover. We propose that three hadronic superfluid vortices must join together to three non-Abelian vortices with different color fluxes with the total color magnetic fluxes canceled out, where the junction is called a colorful boojum.
Ulugbek Yakhshiev🇰🇷 · Hyun-Chul Kim🇰🇷 · Makoto Oka🇯🇵
We investigate the static properties of the nucleon in the presence of strong magnetic fields and discuss the consequent changes of the nucleon structure, based on the Skyrme model. The results show that at large values of the magnetic field ( to ), which is supposed to appear in heavy-ion collision experiments at RHIC energies, the soliton starts to deviate from the spherically symmetric form and its size starts to change. At extremely large values of the magnetic field ( G), which may be found at the LHC experiments, the soliton becomes more compact than in free space. The results also show that in the presence of the external magnetic field, the mass of the nucleon tends to increase in general and the mass degeneracy of the isobars from isospin symmetry will be lifted. We also discuss the changes in the mass difference between the and the nucleon, , due to the influence of the external magnetic field. We find that increases as the strength of the magnetic field grows.
C. Azevedo🇧🇷 · V.P. Goncalves🇧🇷 · B.D. Moreira🇧🇷
In this paper we perform a systematic study of the exclusive dilepton production by interactions in collisions at the LHC Run 2 energies considering different levels of precision for the treatment of the absorptive corrections and for the nuclear form factor. The rapidity and invariant mass distributions are estimated taking into account the experimental cutoffs and a comparison with the recent ALICE and ATLAS data for the and production is presented.
Emanuel Gouveia🇵🇹 · Ricardo Gonçalo🇵🇹 · António Onofre🇵🇹 · Duarte Azevedo🇵🇹
The ATLAS and CMS collaborations recently announced the observation of the associated production of the Higgs boson with a top quark pair () at the LHC. This process depends directly on the the top quark Yukawa coupling and provides access to its properties. In particular, a CP-odd component is allowed in models beyond the Standard Model with extended Higgs sectors. Studies of the feasibility of such a measurement at the 13 TeV LHC were carried out, in the decay channel and with the system decaying through the semileptonic and dileptonic channels. Fast detector simulation and kinematic fits were applied to samples of SM backgrounds and of signal scenarios with different CP-mixing angles of the coupling. Ratios of projections of momenta and angular distributions using boosted reference frames were found to be sensitive to the CP-mixing angle. Those are expected to be robust relatively to modeling uncertainties and are thus presented as good candidates for experimental use. Expected confidence levels for the exclusion of scenarios with a CP-odd component in the top quark Yukawa coupling were obtained, using different observables as discriminants, and are presented for integrated luminosities up to 3 ab, as expected after the full HL-LHC program.
Yu-Sheng Liu🇨🇳 · Wei Wang🇨🇳 · Ji Xu🇨🇳 · Qi-An Zhang🇨🇳 · Jian-Hui Zhang🇩🇪 · Shuai Zhao🇨🇳 · Yong Zhao🇺🇸
Within the framework of large momentum effective theory (LaMET), genenaralized parton distributions (GPDs) can be extracted from lattice calculations of quasi-GPDs through a perturbative matching relation, up to power corrections that are suppressed by the hadron momentum. In this paper, we focus on isovector quark GPDs, including the unpolarized, longitudinally and transversely polarized cases, and present the one-loop matching that connects the quasi-GPDs renormalized in a regularization-independent momentum subtraction (RI/MOM) scheme to the GPDs in MS scheme. We find that the matching coefficient is independent of the momentum transfer squared. As a consequence, the matching for the quasi-GPD with zero skewness is the same as that for the quasi-PDF. Our results provide a crucial input for the determination of quark GPDs from lattice QCD using LaMET.
The existence of a mechanism within the non-Abelian dynamics of QCD that confines quarks and gluons to the interior of hadrons has long been accepted empirically. To explore what this mechanism might look like, this paper examines field-strength descriptions for an extended system of SU(2) charges with spherical symmetry and imposes alternate confining boundary conditions to the time-independent Yang-Mills Maxwell equations. Three types of global solutions to the set of equations can be distinguished: types 0,1,and2. Type-0 solutions evade the nonlinear dynamics associated with the radial magnetic field to describe a topologically trivial bound state. Type-1 and type-2 solutions both require a domain wall of topological charge to separate the interior volume containing the SU(2) charge densities from the exterior volume where the boundary conditions are imposed. Type-1 solutions describe an exterior volume with a radial magnetic field while type-2 solutions contain a sterile exterior volume where all field-strengths vanish. These solutions both describe a non-Abelian "spherical dual topological insulator". the dimensional reduction associated with the imposition of spherical system of SU(2) charges can also be applied to SU(3) charges so this simple exercise is directly relevant to understanding confinement in QCD.
Gabriela Barenboim🇪🇸 · Peter B. Denton🇺🇸 · Stephen J. Parke🇺🇸 · Christoph A. Ternes🇪🇸
In this paper we review different expansions for neutrino oscillation probabilities in matter in the context of long-baseline neutrino experiments. We examine the accuracy and computational efficiency of different exact and approximate expressions. We find that many of the expressions used in the literature are not precise enough for the next generation of long-baseline experiments, but several of them are while maintaining comparable simplicity. The results of this paper can be used as guidance to both phenomenologists and experimentalists when implementing the various oscillation expressions into their analysis tools.
A standing problem in neutrino physics is the consistent and universal definition of oscillating neutrino states as coherent superpositions of massive neutrino states. This problem is solved in a quantum field theoretical framework of neutrino mixing developed in analogy with the Nambu--Jona-Lasinio model for the dynamical generation of nucleon masses. The massive neutrino states are Bogoliubov quasiparticles and their vacuum is a condensate of "Cooper pairs" of massless flavour neutrinos. Their superpositions as oscillating neutrino states have intrinsic quantum coherence by construction. In this quantization framework, the standard phenomenological flavour neutrino states and oscillation probability formula are validated in the ultrarelativistic approximation.
Ursula Laa🇦🇺 · Dianne Cook🇦🇺
Projection pursuit is used to find interesting low-dimensional projections of high-dimensional data by optimizing an index over all possible projections. Most indexes have been developed to detect departure from known distributions, such as normality, or to find separations between known groups. Here, we are interested in finding projections revealing potentially complex bivariate patterns, using new indexes constructed from scagnostics and a maximum information coefficient, with a purpose to detect unusual relationships between model parameters describing physics phenomena. The performance of these indexes is examined with respect to ideal behaviour, using simulated data, and then applied to problems from gravitational wave astronomy. The implementation builds upon the projection pursuit tools available in the R package, tourr, with indexes constructed from code in the R packages, scagnostics, minerva and mbgraphic.
R. Alemany🇨🇭 · C. Burrage🇬🇧 · H. Bartosik🇨🇭 · J. Bernhard🇨🇭 · J. Boyd🇨🇭 · M. Brugger🇨🇭 · M. Calviani🇨🇭 · C. Carli🇨🇭 · N. Charitonidis🇨🇭 · D. Curtin🇨🇦 · A. Dainese🇮🇹 · A. de Roeck🇨🇭 and 52 other authors
Physics Beyond Colliders is an exploratory study aimed at exploiting the full scientific potential of CERN's accelerator complex and its scientific infrastructure in the next two decades through projects complementary to the LHC, HL-LHC and other possible future colliders. These projects should target fundamental physics questions that are similar in spirit to those addressed by high-energy colliders, but that require different types of beams and experiments. A kick-off workshop held in September 2016 identified a number of areas of interest and working groups have been set-up to study and develop these directions. All projects currently under consideration are presented including physics motivation, a brief outline of the experimental set-up and the status of the corresponding beam and detector technological studies. The proposals are also put in context of the worldwide landscape and their implementation issues are discussed.
Paolo Rossi🇮🇹 · Alessandro Strumia🇮🇹 · Riccardo Torre🇨🇭
An important issue in bibliometrics is the weighing of co-authorship in the production of scientific collaborations, which are becoming the standard modality of research activity in many disciplines. The problem is especially relevant in the field of high-energy physics, where collaborations reach 3000 authors, but it can no longer be ignored also in other domains, like medicine or biology. We present theoretical and numerical arguments in favour of weighing the individual contributions as where is the number of co-authors. When counting citations we suggest the exponent , that corresponds to fractional counting. When counting the number of papers we suggest , with the former (latter) value more appropriate for larger (smaller) collaborations. We expect and verify that the index scales as the square root of the average number of co-authors, and define a fractionalized index that does not scale with collaboration size.
* 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.