Particle Physics

We consider dark matter (DM) that interacts with ordinary matter exclusively through an electromagnetic anapole, which is the only allowed electromagnetic form factor for Majorana fermions. We show that unlike DM particles with an electric or magnetic dipole moment, anapole dark matter particles annihilate exclusively into fermions via purely p-wave interactions, while tree-level annihilations into photons are forbidden. We calculate the anapole moment needed to produce a thermal relic abundance in agreement with cosmological observations, and show that it is consistent with current XENON100 detection limits on the DM-nucleus cross-section for all masses, while lying just below the detection threshold for a mass ∼ 30 -40 GeV.

The Large Hadron–Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron–proton and proton–proton operations. This report represents an update to the LHeC’s conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton–nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics prog...

We perform the first amplitude analysis of experimental data using deep neural networks to determine the nature of an exotic hadron. Specifically, we study the line shape of the P c ð4312Þ signal reported by the LHCb collaboration, and we find that its most likely interpretation is that of a virtual state. This method can be applied to other near-threshold resonance candidates.

We construct the amplitudes of πη photoproduction taking into account the effects of the πη -K K interchannel coupling. The idea of our model is close to the molecular description of scalar resonances with exception that apart from the pseudoscalar loops we include also vector mesons in the intermediate state loops. These amplitudes are used to calculate the S-wave cross sections and mass distributions in the πη effective mass region corresponding to the scalar resonances a0(980) and a0( ). The values we obtained for a0(980) are comparable with predictions of other models while the cross section for a0( ) is about an order of magnitude larger than prediction based on the quark model. We show that the amplitudes with loops containing vector mesons calculated in the on-shell approximation are not suppressed in contrast to amplitudes containing only pseudoscalar loops. We estimate the cross sections for the P -and D-waves in the πη channel.

We have analyzed the γp → pK + K -reaction in the K + K -effective mass region around the mass of the φ(1020) meson. The interference of the S-wave contribution with the P -wave has been studied. Both scalar resonances f 0 (980) and a 0 (980) have been taken into account. We obtained a good description of the available experimental data, in particular the mass distributions and the moments of the kaon angular distribution. Our calculations give values of the integrated S-wave total photoproduction cross section between 4 and 7 nb for the K + K -effective mass range around the φ(1020) mass and at the laboratory photon energy near 5 GeV. These numbers favor lower experimental estimates obtained at DESY.

Understanding the spectrum of resonances is directly related to fundamental features of the QCD like the confinement • Photoproduced meson systems are more likely (than eg. pionproduced) to carry exotic quantum numbers Reliable models are badly needed to describe the wealth of the resonance photoproduction data to be expected in near future from JLab (CLAS12 and GlueX), ELSA, MAMI, and SPring-8 experiments

Assuming that the π + π -photoproduction at forward angles and high energies is dominated by one pion exchange we calculate the π + π -mass distributions for low partial waves. Predictions of the model agree well with the experimental data which indicate that the S, P and D waves are dominated by the f 0 (980), ρ(770) and f 2 (1270), resonances respectively.

A summary of the recent ATLAS results at the LHC in Quantum Chromodynamics is given, covering a number of areas that reflect the work of the collaboration on the Bose-Einstein correlations in multi-particle events, the inclusive jet production, the measurements of jet substructure quantities in di-jet events, and the photon-photon scattering exclusive processes.

We show that the cross section of the Δ(1230) production in the γp → pπ + π -reaction at forward angles and with unpolarized photons can be described in terms of gauge invariant one pion t-channel exchange amplitudes. Proper description of the polarized cross sections requires, however, the inclusion of contributions from the baryon exchanges.

The low energy (below 2 GeV) πη channel interaction amplitude becomes an object of interest mainly because of the search for exotic mesons in just beginning to collect data detector GlueX in JLab. Finding and interpretation of expected weak signals from these states require a comparison with a very accurate amplitude containing standard (q q) states i.e. a 0 (980) and a 0 (1450). The main problem in the determination of such amplitude is a total absence of data about the phases and inelasticities in the elastic and inelastic region. In addition, it is necessary to take into account the next two coupled higher channels -K K and πη . Presented here amplitude is based on separable potential model (working very well for the scalar-isoscalar ππ interactions) with only 9 free parameters. To determine such 3-coupled channel amplitude, the following information has been taken into account: experimental branching ratios and positions of both a 0 resonances, theoretical couplings, scattering length from ChPT and value of squared radius of the πη form factor. Phase shifts, inelasticities and cross sections in all single and crossed channels are presented.

We present the coupled channel model of the scalar isovector resonance photoproduction including the πη, KK and πη ′ channels and calculate resulting mass distribution and the cross section in the πη channel. We show that the shape of this mass distribution, is strongly affected by the phase of background amplitude. We also discuss the effect of inclusion the πη ′ channel on the overall isovector photoproduction process.

We present a phenomenological analysis of the π + π -photoproduction data obtained by the CLAS collaboration at the Thomas Jefferson Laboratory. A special emphasis is put on the interference pattern observed in the moments of angular distribution for the π + π -efective masses around 1 GeV. This pattern is attributed to the photoproduction of the scalar-isoscalar resonance f 0 (980). By fitting the model parameters to the data we obtain the strengths of the resonant and nonresonant parts of the S-wave photoproduction amplitude. We calculate the f 0 (980) photoproduction cross section which is smaller than previous estimations by a factor of about 5. A new estimation of the product of the σ meson couplings to nucleon and to the γρ system |g NNσ g γρσ | is given.

Results of a new analysis of the K + K -photoproduction at two photon energies E γ = 4 GeV and 5.65 GeV with a particular emphasis on the S-wave production are presented. We show that the proper treatment of all the helicity components of the S-and P -waves enables one to eliminate the reported discrepancies in the extraction of the Swave photoproduction cross section from experimental data.

We construct the amplitudes of πη photoproduction taking into account the effects of the πη -K K interchannel coupling. The idea of our model is close to the molecular description of scalar resonances with exception that apart from the pseudoscalar loops we include also vector mesons in the intermediate state loops. These amplitudes are used to calculate the S-wave cross sections and mass distributions in the πη effective mass region corresponding to the scalar resonances a0(980) and a0( ). The values we obtained for a0(980) are comparable with predictions of other models while the cross section for a0( ) is about an order of magnitude larger than prediction based on the quark model. We show that the amplitudes with loops containing vector mesons calculated in the on-shell approximation are not suppressed in contrast to amplitudes containing only pseudoscalar loops. We estimate the cross sections for the P -and D-waves in the πη channel.

Tensor meson photoproduction is described as either a direct production process or a consequence of the final state ππ interactions. We calculate the mass distributions for selected partial waves and confront our predictions with the measurements of the CLAS experiment. We also point out the structures in the photoproduction amplitudes which may result in observable effects able to indicate the dominant tensor meson photoproduction mechanism.

We highlight the need for the development of comprehensive amplitude analysis methods to further our understanding of hadron spectroscopy. Reaction amplitudes constrained by first principles of S-matrix theory and by QCD phenomenology are needed to extract robust interpretations of the data from experiments and from lattice calculations. In the last two decades, high-energy physics experiments have delivered a lot of unexpected exotic hadron resonances, that challenge the minimal quark model lore of baryons with three quarks and mesons with a quark-antiquark pair. Candidates for tetraquarks, pentaquarks, molecules, and hadrons with gluonic degrees of freedom have been found [1,. Establishing the existence of isolated resonances that go beyond the minimal quark model is just the first step: one needs to identify the complete multiplets and study the differences and similarities among their members. This

We report on the results of the first measurement of exclusive f 0 ð980Þ meson photoproduction on protons for E ¼ 3:0-3:8 GeV and Àt ¼ 0:4-1:0 GeV 2 . Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the þ À channel by performing a partial wave analysis of the reaction p ! p þ À . Clear evidence of the f 0 ð980Þ meson was found in the interference between P and S waves at M þ À $ 1 GeV. The S-wave differential cross section integrated in the mass range of the f 0 ð980Þ was found to be a factor of about 50 smaller than the cross section for the meson. This is the first time the f 0 ð980Þ meson has been measured in a photoproduction experiment.

The model is presented to describe the f2(1270) meson photoproduction as a result of pionpion interactions in the final state. Treating tensor mesons as objects dynamically created due to final state interactions is a convenient and straightforward way to employ data from ππ scattering like phase shifts and inelasticities for description of (photo)production reactions while retaining proper analytical structure of amplitudes, two particle unitarity and crossing symmetry. The model presented here can provide experimentally testable quantities like differential cross sections and ππ mass distributions as well as the strengths of partial waves corresponding to various f2(1270) helicities which are essential for partial wave analyses. It can also be used to compute moments of angular distribution and spin density matrix elements where partial wave interference effects are important.

We study the possibility of detecting the neutral Higgs bosons predicted in the Minimal Supersymmetric Standard Model (h 0 , H 0 , A 0 ), with the reactions e + e -→ b bh 0 (H 0 , A 0 ), using the helicity formalism. We analyze the region of parameter space (m A 0tan β) where h 0 (H 0 , A 0 ) could be detected in the limit when tan β is large. The numerical computation is done for the energy which is expected to be available at LEP-II ( √ s = 200 GeV ) and for a possible Next Linear e + e - Collider ( √ s = 500 GeV ).

Lepton family number violation processes arise in the SU(6) L⊗ U(1) Y model due to the presence of an extra neutral gauge boson, Z′, with family changing couplings, and due to the fact that this model demands the existence of heavy exotic leptons. The mixing of the standard Z with Z′ and the mixing of ordinary leptons with exotic ones induce together family changing couplings on the Z and therefore nonvanishing rates for lepton family number violation processes, such as [Formula: see text], [Formula: see text] and μ→eγ. Additional contributions to the processes μ→eγ and [Formula: see text] are induced from the mass generation mechanism. This last type of contributions may compete with the above one, depending on the masses of the scalars which participate in the diagrams which generate radiatively the masses of the charged leptons. Using the experimental data we compute some bounds for the mixings parameters and for the masses of the scalars.

ACORDE (A COsmic Ray DEtector in ALICE) will be part of the ALICE detector at LHC and its objective is to provide a cosmic ray trigger (level 0). ACORDE will consist of an array of plastic scintillators placed on the top sides of the ALICE magnet. We describe the ...

This synthesis formalizes the integration of Bogaert's Symbolic Transport Framework (STF) into Omniological Resonance Theory (ORT), aligning AI dispatch systems and human logistics networks with the 7.5-dimensional harmonic spacetime model. It positions drivers as coherent resonance nodes, AI as symbolic dispatch filters, and tokens as entangled state markers within a non-Euclidean transport lattice. Fractal recursion, informatic fields, and octonionic routing symmetry are unified through a resonant transport function, modeling freight logistics as a semiconscious field.

We present mass spectrum and magnetic moments of the nnQQ states, where n = u, d, s and Q = c, b. We solve four-body Schrödinger equation with a quark potential model by using diffusion Monte Carlo (DMC) method. The quark potential is based on the Coulomb, confinement and spin-spin interaction terms. We find mass and magnetic moment of the T + cc state as M T + cc = 3892 MeV and µ = 0.28µN ,respectively. We also find the mass and magnetic moment of T - bb as M T - bb = 10338 MeV and µ = -0.32µN , respectively. We find some bound state candidates of doubly heavy tetraquark systems with I(J P ) = 0(1) + nn bb , I(J P ) = 0(0) + nnc b, I(J P ) = 0(1) + nnc b, and I(J P ) = 1/2(1) + ns bb . We compare our results with other approaches in the literature.

We visited mass spectra and decay constants of pseudoscalar and vector heavy-light mesons (𝐵, 𝐵 푠 , 𝐷, and 𝐷 푆 ) in the framework of QCD sum rule and quark model. The harmonic oscillator wave function was used in quark model while a simple interpolating current was used in QCD sum rule calculation. We obtained good results in accordance with the available experimental data and theoretical studies.

We study D + s D - s and D D states assuming that they are hadronic molecules with J P C = 0 ++ quantum number. We use two-point QCD sum rule formalism and extract the mass and decay constant values of these states. We take into account contributions of various quark, gluon, and mixed vacuum condensates up to dimension eight. The extracted mass and decay constant values of D D and D + s D - s states read as M D D = 3795 +85 -82 MeV, f D D = 1.70 +0.33 -0.29 × 10 -2 GeV 5 , and M D + s D - s = 3983 +93 -88 MeV, f D + s D - s = 2.52 +0.64 -0.54 × 10 -2 GeV 5 , respectively. The predicted mass of D + s D - s state is in good agreement with the recent LHCb observation and supports quantum number and molecular picture assignments. A possible observation of D D state would help for establishing the lowest four-quark state in charmonium sector.

Inspired by the discovery of the doubly-charmed and doubly-charged Ξ ++ cc baryon, in this present work, we investigate spin-1/2 and spin-3/2 mass spectra and magnetic moments of ccu baryon in quark-diquark model with a nonrelativistic potential. In the quark-diquark picture, the three-body problem of the ccu baryon is reduced to the two-body bound state problem. We obtained ground and radially excited mass spectra and magnetic moments of the ground state. Ground state mass spectra agree well with the results in the literature, especially with lattice QCD computations. Predictions for the magnetic moment are compatible with the literature. According to our results, cu diquark clustering in the Ξ ++ cc baryon is more favorable than the cc diquark clustering.

In this study, the magnetic moments of the spin-1/2 triply-heavy baryons have been calculated using both light-cone QCD sum rules and Quark-diquark model. Theoretical investigations on magnetic moments of the triply-heavy baryons, are crucial as their results can help us better understand their internal structure and the dynamics of the QCD as the theory of the strong interaction. We compare the results extracted for the magnetic moment with the existing theoretical predictions. It is seen that the obtained magnetic moment values are quite compatible with the results in the literature.

Motivated by the very recent discovery of fully open-flavor exotic states X0(2900) and X1(2900) by the LHCb Collaboration, we study possible interpretations of these exotic states by QCD Sum Rules method. A molecular picture is used for X0(2900) whereas a diquark-antidiquark tetraquark picture is used for X1(2900). Obtained results for masses are in good agreement with the observed masses in the experiment. Moreover, a Monte-Carlo based analysis within QCD Sum Rules is made to investigate the possible assignments for X0(2900) and X1(2900).

In this work, we have obtained mass spectra, radiative decay widths and strong decay widths of newly observed excited Ω - b states, i.e. Ω b (6316) -, Ω b (6330) -, Ω b (6340) -, and Ω b (6350) -. Mass spectrum is obtained in Hypercentral Constituent Quark Model (hCQM) by solving six-dimensional nonrelativistic Schrödinger equation via Artificila Neural Network (ANN). In this respect, radiative decay widhts are calculated by a generalization of a framework from meson to baryon. Also, strong decay widths of the low-lying Ω b states within 3 P0 model are calculated. Obtained results are presented with the comparison of available experimental data and other theoretical studies.

Recently, the LHCb experiment announced the observation of hidden-charm pentaquark states , , and near and thresholds. In this present work, we studied these pentaquarks in the framework of the nonrelativistic quark model with four types of potential. We solved five-body Schrödinger equation by using the artificial neural network method and made predictions of parities for these states, which are not yet determined by experiment. The mass of another possible pentaquark state near the with is also calculated.

We visited mass spectra and decay constants of pseudoscalar and vector heavy-light mesons (B, Bs, D, and DS) in the framework of QCD sum rule and quark model. The harmonic oscillator wave function was used in quark model while a simple interpolating current was used in QCD sum rule calculation. We obtained good results in accordance with the available experimental data and theoretical studies.

In this paper we revisited phenomenological potentials. We studied S-wave heavy quarkonium spectra by two potential models. The first one is power potential and the second one is logarithmic potential. We calculated spin averaged masses, hyperfine splittings, Regge trajectories of pseudoscalar and vector mesons, decay constants, leptonic decay widths, two-photon and two-gluon decay widths, and some allowed M1 transitions. We studied ground and 4 radially excited S-wave charmonium and bottomonium states via solving nonrelativistic Schrödinger equation. Although the potentials which were studied in this paper are not directly QCD motivated potential, obtained results agree well with experimental data and other theoretical studies.

presents many surprises after its discovery more than ten years ago. Understanding its properties is crucial to understand the spectrum of possible exotic mesons. In this work, X (3872) meson and its heavy quark spin symmetry (HQSS) partners (including the mesons in the bottom sector) are studied within the QCD Sum Rules approach using a current motivated by the molecular picture of X (3872). We predict four heavy partners to X (3872) and bottomonium with the masses and J PC quantum numbers. Obtained results are in good agreement with the previous studies and available experimental data within errors.

We present an example of a realistic Higgsless model that makes use of alternative SU (2) R assignments for the top and bottom quarks recently proposed by Agashe et al. which results in an enhanced custodial symmetry. Using these new representations reduces the deviations in the Zb b coupling to ∼ 4% for a wide range of parameters, while this remaining correction can also be eliminated by varying the localization parameter (bulk mass) for b r .

We consider fermions on an extra dimensional interval. We find the boundary conditions at the ends of the interval that are consistent with the variational principle, and explain which ones arise in various physical circumstances. We apply these results to higgsless models of electroweak symmetry breaking, where electroweak symmetry is not broken by a scalar vacuum expectation value, but rather by the boundary conditions of the gauge fields. We show that it is possible to find a set of boundary conditions for bulk fermions that would give a realistic fermion mass spectrum without the presence of a Higgs scalar, and present some sample fermion mass spectra for the standard model quarks and leptons as well as their resonances. * For other possibilities of utilizing extra dimensions for electroweak symmetry breaking see .

We calculate the spectrum of glueball masses in non-supersymmetric Yang-Mills theory in three and four dimensions, based on a conjectured duality between supergravity and large N gauge theories. The glueball masses are obtained by solving supergravity wave equations in a black hole geometry. We find that the mass ratios are in good numerical agreement with the available lattice data. We also compute the leading (g~MN)-1 corrections to the glueball masses, by taking into account stringy corrections to the supergravity action and to the black hole metric. We find that the corrections to the masses are negative and of order (g~MN)-3 1 2 • Thus for a fixed ultraviolet cutoff the masses decrease as we decrease the 't Hooft coupling, in accordance with our expectation about the continuum limit of the gauge theories.

We consider various constraints on Higgsless models of electroweak symmetry breaking based on a bulk SU(2) L ×SU(2) R ×U(1) B-L gauge group in warped space. First we show that the S parameter which is positive if fermions are localized on the Planck brane can be lowered (or made vanishing) by changing the localization of the light fermions. If the wave function of the light fermions is almost flat their coupling to the gauge boson KK modes will be close to vanishing, and therefore contributions to the S parameter will be suppressed. At the same time the experimental bounds on such Z ′ and W ′ gauge bosons become very weak, and their masses can be lowered to make sure that perturbative unitarity is not violated in this theory before reaching energies of several TeV. The biggest difficulty of these models is to incorporate a heavy top quark mass without violating any of the experimental bounds on bottom quark gauge couplings. In the simplest models of fermion masses a sufficiently heavy top quark also implies an unacceptably large correction to the Zb b vertex and a large splitting between the KK modes of the top and bottom quarks, yielding large loop corrections to the T -parameter. We present possible directions for model building where perhaps these constraints could be obeyed as well.

We examine the possibility that the recently discovered 125 GeV higgs-like resonance actually corresponds to a dilaton: the Goldstone boson of scale invariance spontaneously broken at a scale f . Comparing to LHC data we find that a dilaton can reproduce the observed couplings of the new resonance as long as f ≈ v, the weak scale. This corresponds to the dynamical assumption that only operators charged under the electroweak gauge group obtain VEVs. The more difficult task is to keep the mass of the dilaton light compared to the dynamical scale, Λ ∼ 4πf , of the theory. In generic, non-supersymmetric theories one would expect the dilaton mass to be similar to Λ. The mass of the dilaton can only be lowered at the price of some percent level (or worse) tuning and/or additional dynamical assumptions: one needs to suppress the contribution of the condensate to the vacuum energy (which would lead to a large dilaton quartic coupling), and to allow only almost marginal deformations of the CFT.

Vacuum energy changes during cosmological phase transitions and becomes relatively important at epochs just before phase transitions. For a viable cosmology the vacuum energy just after a phase transition must be set by the critical temperature of the next phase transition, which exposes the cosmological constant problem from a different angle. Here we propose to experimentally test the properties of vacuum energy under circumstances different from our current vacuum. One promising avenue is to consider the effect of high density phases of QCD in neutron stars. Such phases have different vacuum expectation values and a different vacuum energy from the normal phase, which can contribute an order one fraction to the mass of neutron stars. Precise observations of the mass of neutron stars can potentially yield information about the gravitational properties of vacuum energy, which can significantly affect their mass-radius relation. A more direct test of cosmic evolution of vacuum energy could be inferred from a precise observation of the primordial gravitational wave spectrum at frequencies corresponding to phase transitions. While traditional cosmology predicts steps in the spectrum determined by the number of degrees of freedom both for the QCD and electroweak phase transitions, an adjustment mechanism for vacuum energy could significantly change this. In addition, there might be other phase transitions where the effect of vacuum energy could show up as a peak in the spectrum.

We explore how to protect extra dimensional models from large flavor changing neutral currents by using bulk and brane flavor symmetries. We show that a GIM mechanism can be built in to warped space models such as Randall-Sundrum or composite Higgs models if flavor mixing is introduced via UV brane kinetic mixings for right handed quarks. We give a realistic implementation both for a model with minimal flavor violation and one with next-to-minimal flavor violation. The latter does not suffer from a CP problem. We consider some of the existing experimental constraints on these models implied by precision electroweak tests.

We consider various constraints on Higgsless models of electroweak symmetry breaking based on a bulk SU(2) L ×SU(2) R ×U(1) B-L gauge group in warped space. First we show that the S parameter which is positive if fermions are localized on the Planck brane can be lowered (or made vanishing) by changing the localization of the light fermions. If the wave function of the light fermions is almost flat their coupling to the gauge boson KK modes will be close to vanishing, and therefore contributions to the S parameter will be suppressed. At the same time the experimental bounds on such Z and W gauge bosons become very weak, and their masses can be lowered to make sure that perturbative unitarity is not violated in this theory before reaching energies of several TeV. The biggest difficulty of these models is to incorporate a heavy top quark mass without violating any of the experimental bounds on bottom quark gauge couplings. In the simplest models of fermion masses a sufficiently heavy top quark also implies an unacceptably large correction to the Zb b vertex and a large splitting between the KK modes of the top and bottom quarks, yielding large loop corrections to the T -parameter. We present possible directions for model building where perhaps these constraints could be obeyed as well.