The Masses of Heavy Pentaquarks in Non-Relativistic Bethe-Salpeter Quark Model

The exotic particles such as the pentaquarks are to strengthen understanding of important interactions and the principle of QCD in which pentaquarks contain two heavy- valence quarks. The structure of two bodies including an antiquark and two-diquark is introduced. A new potential for quark interaction is suggested which includes the logarithm potential, the linear potential, and the spin-spin interaction. The suggested potential is included in the framework of spinless of Bethe-Salpeter equation. A comparison with other works is presented which provides a good description of pentaquarks.

Photon and leptons induced processes at the LHC

We study a few basic photon- and lepton-initiated processes at the LHC which can be computed using the recently developed photon and lepton parton densities. First, we consider the production of a massive scalar particle initiated by lepton-antilepton annihilation and photon-photon fusion as representative examples of searches of exotic particles. Then we study lepton-lepton scattering, since this Standard-Model process may be observable at the LHC. We examine these processes at leading and next-to-leading order and, using the POWHEG method, we match our calculations to parton shower programs that implement the required lepton or photon initial-states. We assess the typical size of cross-sections and their uncertainties and discuss the preferred choices for the factorization scale. These processes can also be computed starting directly from the lepto-production hadronic tensor, leading to a result where some collinear-enhanced QED corrections are missing, but all strong corrections are included. Thus, we are in the unique position to perform a comparison of results obtained via the factorization approach to a calculation that does not have strong corrections. This is particularly relevant in the case of lepton-scattering, that is more abundant at lower energies where it is affected by larger strong corrections. We thus compute this process also with the hadronic-tensor method, and compare the results with those obtained with POWHEG. Finally, for some lepton-lepton scattering processes, we compare the size of the signal to the main quark-induced background, which is double Drell-Yan production, and outline a preliminary search strategy to enhance the signal to background ratio.

Single production of vector-like quarks: the effects of large width, interference and NLO corrections

We provide a comprehensive discussion, together with a complete setup for simulations, relevant for the production of a single vector-like quark at hadron colliders. Our predictions include finite width effects, signal-background interference effects and next-to-leading order QCD corrections. We explicitly apply the framework to study the single production of a vector-like quark T with charge 2/3, but the same procedure can be used to analyse the single production of vector-like quarks with charge −4/3, −1/3, 2/3 and 5/3, when the vector-like quark interacts with the Standard Model quarks and electroweak bosons. Moreover, this procedure can be straightforwardly extended to include additional interactions with exotic particles. We provide quantitative results for representative benchmark scenarios characterised by the T mass and width, and we determine the role of the interference terms for a range of masses and widths of phenomenological significance. We additionally describe in detail, both analytically and numerically, a striking feature in the invariant mass distribution appearing only in the T → th channel.

Constraints on Theoretical Predictions Beyond the Standard Model from the Casimir Effect and Some Other Tabletop Physics

We review the hypothetical interactions predicted beyond the Standard Model which could be constrained by using the results of tabletop laboratory experiments. These interactions are described by the power-type potentials with different powers, Yukawa potential, other spin-independent potentials, and by the spin-dependent potentials of different kinds. In all these cases the current constraints on respective hypothetical interactions are considered which follow from the Casimir effect and some other tabletop physics. The exotic particles and constraints on them are discussed in the context of problems of the quantum vacuum, dark energy, and the cosmological constant.

The structural design of the decay volume for the Search for Hidden Particles (SHIP) project

The Search for Hidden Particles (SHiP) experiment is a new general-purpose fixed target facility proposed at the CERN Super Proton Synchrotron (SPS) accelerator to search for long-lived exotic particles associated with Hidden Sectors and Dark Matter. This paper reports on the structural design of SHiP’s decay volume, a > 2000 m3 conical vessel under vacuum that should host several large particle physics detector systems. In the field of structural and seismic engineering, the design study in a very multidisciplinary international collaboration has represented a stimulating research challenge. The goal of the design of the decay is to produce a structure as light and as slim as possible to stay within the geometrical envelop determined in the physics simulations. A complete study has been performed with all the steps from the conceptual design, including the interaction with other components and the plant systems, to the assembly procedures for the decay volume realization. The complexity of the case study has been driven by the need of finding the appropriate compromise between the physics performance, the structural aspects, the executive, constructive and operational issues, and the economical constraints. The assembly strategy, the welding techniques, and the expected construction time are discussed in view of the extremely complex installation phase. Building Integrated Model (BIM) methodology is also proposed as an essential tool to coordinate the entire process of designing and managing not only the decay volume but the entire project.

Charged scalar production at the compact linear collider for the $$S_3 \otimes \mathbb {Z}_2$$ model

We present a model with $$S_3 \otimes \mathbb {Z}_2$$ S 3 ⊗ Z 2 model plus a sterile neutrino and its phenomenological expectations for the production of charged scalars at the compact linear collider. At tree level, our model predicts a total cross section in between 0.1 and $$10^{-5}$$ 10 - 5 pb for the $$e^- e^+ \rightarrow H^+ H^-$$ e - e + → H + H - process, considering all possible mass values for the charged scalar in the CLIC experiment. We also show that this prediction holds regardless of the masses of the other exotic particles and their couplings. We also show that an indirect detection from its effects in the $$e \overline{e} \rightarrow e \overline{e}$$ e e ¯ → e e ¯ + missing energy process is possible under specific conditions, or a direct detection under other circumstances. However, one cannot use this process to study the sterile neutrinos present in this model, given that they have a small influence in the total cross-section for the direct detection of the exotic scalar to be possible.

Fractional statistics in anyon collisions

Two-dimensional systems can host exotic particles called anyons whose quantum statistics are neither bosonic nor fermionic. For example, the elementary excitations of the fractional quantum Hall effect at filling factor ν = 1/m (where m is an odd integer) have been predicted to obey Abelian fractional statistics, with a phase ϕ associated with the exchange of two particles equal to π/m. However, despite numerous experimental attempts, clear signatures of fractional statistics have remained elusive. We experimentally demonstrate Abelian fractional statistics at filling factor ν = ⅓ by measuring the current correlations resulting from the collision between anyons at a beamsplitter. By analyzing their dependence on the anyon current impinging on the splitter and comparing with recent theoretical models, we extract ϕ = π/3, in agreement with predictions.