The aim of the proposed CERN Gamma Factory is to produce ≈1017 photons per second with energies up to 400 MeV. The photon beam intensity is expected to be a factor of O(107)$\mathcal {O}(10^7)$ ...larger than that of the presently available photon beams in the MeV energy range. In this work, its potential to probe physics beyond the Standard Model is explored. In particular, searches for axion like particles (ALPs) with dominant couplings to photons are discussed and various production scenarios—fixed target, photon–photon collision, and conversion by a magnetic field—and detection schemes considered—via decay to photons or back‐conversion. It is found that the Gamma Factory in a fixed target mode can probe ALPs with mass ma≲O(100MeV)$m_a \lesssim \mathcal {O}(100\,\mathrm{MeV})$ and decay constants larger than 107 GeV, improving by an order of magnitude the discovery potential of previous beam dump experiments.
In this work, the potential of the proposed CERN Gamma Factory to probe physics beyond the Standard Model, namely axion like particles with dominant couplings to photons, is explored. Various production scenarios and detection schemes are considered. In some configurations, an improvement by an order of magnitude of the discovery potential compared to previous beam dump experiments is found.
The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark ...energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models.
Charged Lepton Flavor Violation is expected to be one of the most powerful tools to reveal physics beyond the Standard Model. The COMET experiment aims to search for the neutrinoless coherent ...transition of a muon into an electron in the field of a nucleus. Muon-to-electron conversion has never been observed, and can be, and would be, clear evidence of new physics if discovered. The experimental sensitivity of this process, defined as the ratio of the muon-to-electron conversion rate to the total muon capture rate, is expected to be significantly improved by a factor of 100 to 10,000 in the coming decade. The COMET experiment will take place at J-PARC with single event sensitivities of the orders of 10−15 and 10−17 in Phase-I and Phase-II, respectively. The ambitious goal of the COMET experiment is achieved by realizing a high-quality pulsed beam and an unprecedentedly powerful muon source together with an excellent detector apparatus that can tolerate a severe radiation environment. The construction of a new beam line, superconducting magnets, detectors and electronics is in progress towards the forthcoming Phase-I experiment. We present the experimental methods, sensitivity and backgrounds along with recent status and prospects.
A light charged Higgs boson has been searched for at the Large Hadron Collider (LHC) via top (anti)quark decay, i.e., t→bH+, if kinematically allowed. In this contribution, we propose new channels ...for light charged Higgs boson searches via the pair productions pp→H±h/A and pp→H+H− at the LHC in the context of the Two-Higgs Doublet Model (2HDM) Type-I. By focusing on a case where the heavy H state is the Standard Model (SM)-like one already observed, we investigate the production of the aforementioned charged Higgs bosons and their bosonic decay channels, namely, H±→W±h and/or H±→W±A. We demonstrate that such production and decay channels can yield substantial alternative discovery channels for H± bosons at the LHC. Finally, we propose eight benchmark points (BPs) to motivate the search for such signatures.
We review the current status of the long-term programme of numerical investigation of Sp(2N) gauge theories with and without fermionic matter content. We start by introducing the phenomenological as ...well as theoretical motivations for this research programme, which are related to composite Higgs models, models of partial top compositeness, dark matter models, and in general to the physics of strongly coupled theories and their approach to the large-N limit. We summarise the results of lattice studies conducted so far in the Sp(2N) Yang–Mills theories, measuring the string tension, the mass spectrum of glueballs and the topological susceptibility, and discuss their large-N extrapolation. We then focus our discussion on Sp(4), and summarise the numerical measurements of mass and decay constant of mesons in the theories with fermion matter in either the fundamental or the antisymmetric representation, first in the quenched approximation, and then with dynamical fermions. We finally discuss the case of dynamical fermions in mixed representations, and exotic composite fermion states such as the chimera baryons. We conclude by sketching the future stages of the programme. We also describe our approach to open access.
There exists a puzzling disagreement between the results for the neutron lifetime obtained in experiments using the beam technique versus those relying on the bottle method. A possible explanation of ...this discrepancy postulates the existence of a beyond-Standard-Model decay channel of the neutron involving new particles in the final state, some of which can be dark matter candidates. We review the current theoretical status of this proposal and discuss the particle physics models accommodating such a dark decay. We then elaborate on the efforts undertaken to test this hypothesis, summarizing the prospects for probing neutron dark decay channels in future experiments.
Flavour changing neutral current (FCNC) processes are described by loop diagrams in the Standard Model (SM), while in 331 models, based on the gauge group SU(3)C×SU(3)L×U(1)X, they are dominated by ...tree-level exchanges of a new heavy neutral gauge boson Z′. By exploiting this feature, observables related to FCNC decays of K, Bd and Bs mesons can be considered in several variants of 331 models. The variants are distinguished by the value of a parameter β that plays a key role in this framework. Imposing constraints on the ΔF=2 observables, we select possible ranges for the mass of the Z′ boson in correspondence to the values β=±k/3, with k=1,2. The results are used to determine the impact of 331 models on b→s processes and on the correlations among them, in the light of new experimental data recently released.
In this letter, we follow the hypothesis that the tangent bundle (TB) with the central extended little groups of the SO(3, 1)⋊T(1, 3) group as gauge group is the underlying geometric structure for a ...unified theory of the fundamental physical interactions. Based on the geometry of the TB, recently, I presented a generalized theory of electroweak interaction in 1. The vertical (internal) Laplacian of the tangent bundle possesses the same form as the Hamiltonian of a 2D semiconductor quantum Hall system. The three families of leptons and quarks, unlike in the SM, are distinguished by a new quantum number. Here, it will be shown that the SU(3) color symmetry for strong interaction arises as an emergent symmetry similar to Chern- Simon gauge symmetries in multicomponent quantum Hall systems and fractional charge quantization of quarks can be understood by a binding of two vortices to a quark, turning it into a composite quark. The analogy with the anomalous quantum Hall effect could hint at the possible existence of exotic quark states with a hypercharge of e/5. Note that based on translational transformations in the TB geometry previously a gauge theoretical understanding of gravity has been achieved. Therefore, the TB can be considered as the underlying geometry that could constitute a possible way for the unification of the known fundamental forces.
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