Yotam Soreq

Mechanisms of mesogenesis generate the baryon asymmetry and dark matter of the Universe through late-time decays of Standard Model mesons into baryons and dark matter states. Utilizing the C P violation in the meson systems themselves, the resulting baryon asymmetry is directly controlled by collider observables, the C P asymmetry A C P , and the branching fraction for the meson decays. Experimental probes of these decays place strong constraints on the amount of C P violation required, placing it well above observed limits in meson mixing. Additionally, strong lower bounds on the proton lifetime seemingly rule out mesogenesis mechanisms which use D mesons. In this work, we propose to circumvent these constraints by “morphing” the mass of the dark sector particles using a late-time phase transition. The change in mass of the final decay products kinematically excludes meson and proton decays, relaxing the constraints on the model parameter space.

A bstract: We use the amplitude formulation of the SMEFT to introduce a spurion analysis of the SMEFT low-energy amplitudes in terms of the Higgs VEV. Each SMEFT contact-term is given as a sum of a few spurion structures, whose number depends on the electroweak charges of the external legs. The coefficients of these structures involve singlet combinations of Higgses from higher-order SMEFT contributions. We use this to derive the spurion expansions of the W - and Z -boson masses and mixing, and their three-point couplings to fermions. The textures of these couplings are saturated by the dimension-eight SMEFT. Our analysis can be generalized to higher-point amplitudes and nonzero Yukawa couplings.

A bstract: We present a covariant framework for analyzing the interactions and decay rates of axion-like particles (ALPs) that couple to both gluons and quarks. We identify combinations of couplings that are invariant under quark-field redefinitions, and use them to obtain physical expressions for the prominent decay rates of such ALPs, which are compared with previous calculations for scenarios where ALPs couple exclusively to quarks or to gluons. Our framework can be used to obtain ALP decay rates for arbitrary ALP couplings to gluons and quarks across a broad range of ALP masses.

Beam dump experiments represent an effective way to probe new physics in a parameter space, where new particles have feeble couplings to the Standard Model sector and masses below the GeV scale. The LUXE experiment, designed primarily to study strong-field quantum electrodynamics, can be used also as a photon beam dump experiment with a unique reach for new spin-0 particles in the 10–350 MeV mass and 10 − 6 – 10 − 3 GeV − 1 couplings to photons ranges. This is achieved via the “new physics search with optical dump” (NPOD) concept. While prior estimations were obtained with a simplified model of the experimental setup, in this work we present a systematic study of the new physics reach in the full, realistic experimental apparatus, including an existing detector to be used in the LUXE NPOD context. We furthermore investigate updated scenarios of LUXE’s experimental plan and confirm that our results are in agreement with the original estimations of a background-free operation.

A bstract: We explore the possibility that the interactions of a light scalar singlet, which mixes with the Standard Model (SM) Higgs, also receive other UV contributions of comparable size. We focus, in particular, on the flavor aligned limit, where couplings of the light scalar to the SM are almost flavor diagonal, but not necessarily proportional to the Higgs Yukawa couplings. The phenomenology of such a general flavor aligned light scalar differs from both the Higgs-mixed scalar, as well as from a general axion-like particle. We explore this for light scalar masses below a few hundred MeV, such that they can be produced in kaon decays, and in decays of η and η ^′ mesons, and the transitions described using chiral perturbation theory. We then derive constraints on the light scalar interactions, assuming that light scalar decays are either just into photons or are invisible. We also discuss several UV examples of such light scalar models: a two-Higgs doublet model extended by a light scalar, a light dilaton from the dark sector, and a SM extended by heavy vector-like quarks and a light scalar. For the latter we also performed matching onto low energy theory at one-loop.

A bstract: Part of the energy created in deuterium-tritium fusion reactors is carried away from plasma by a high-intensity neutron flux, which is then absorbed by the reactor’s inner walls. The neutron flux can be used to sustain the reaction by the following mechanism: the walls are coated with lithium-rich breeding blankets , in which a fraction of neutrons interacts with lithium, creating tritium, which can be, in turn, used a fuel for the main reaction. The interactions of neutrons with the materials within the breeding blanket can also result in the production of dark sector particles, feebly interacting light scalars or pseudoscalars, via nuclear transitions. We estimate the potential size of such dark sector flux outside the reactor and consider possible detection methods at current and future thermonuclear fusion reactors. In our analysis, we take into account all other current bounds, recasting also the SNO axion bound for a CP even scalar. We find that year-long searches at current and future reactors can set leading constraints on dark scalar- and dark pseudoscalar-nucleon couplings.

We explore the potential of precision spectroscopy of heavy exotic atoms where electrons are substituted by negative hadrons to detect new force carriers with hadronic couplings. The selected transitions are unaffected by nuclear contact terms, thus enabling highly accurate calculations using bound-state QED, provided that the nuclear polarization is under control. Alternatively, we demonstrate that the dipole polarizability, a fundamental property of nuclei, can be extracted from the spectroscopy of exotic atoms in a novel way by combining two transitions while maintaining high sensitivity to new physics. Based on existing data, we extracted world-leading bounds on mediator masses ranging from 0.1 to 10 MeV for two benchmark models and show that forthcoming experiments could enhance the sensitivity to new physics by 2 orders of magnitude.

The anomalous magnetic moment of the muon (a _μ ) provides a stringent test of the quantum nature of the Standard Model (SM) and its extensions. To probe beyond the SM physics, one needs to be able to subtract the SM contributions, which consists of a non-perturbative part, namely, the hadronic vacuum polarization (HVP) of the photon. The state of the art is to predominantly use two different methods to extract this HVP: lattice computation, and dispersion relation-based, data-driven method. Thus one can construct different forms of the “a _μ test” which compares the precise measurement of a _μ to its theory prediction. Additionally, this opens the possibility for another subtle test, where these two “theory” predictions themselves are compared against each other, which is denoted as the “HVP-test”. This test is particularly sensitive to hadronic scale new physics. Therefore, in this work, we consider an SM extension consisting of a generic, light ~ (100 MeV – 1 GeV) vector boson and study its impact on both tests. We develop a comprehensive formalism for this purpose. We find that in the case of data-driven HVP being used in the a _μ test, the new physics contributions effectively cancel for a flavor-universal vector boson. As an illustration of these general results, we consider two benchmark models: i) the dark photon (A ^′) and ii) a gauge boson coupled to baryon-number (B). Using a combination of these tests, we are able to constrain the parameter space of B and A ^′, complementarily to the existing limits. As a spin-off, our preliminary analysis of the spectrum of the invariant mass of 3π in events with ISR at the B− factories (BaBar, Belle) manifests the value of such a study in searching for B → 3π decay, thus motivating a dedicated search by experimental collaborations.

A Muon (Synchrotron) Ion Collider (MuSIC) can be the successor to the Electron-Ion Collider at Brookhaven National Laboratory, as well as the ideal demonstrator facility for a future multi-TeV Muon Collider. Besides its rich nuclear physics and Standard Model particle physics programs, in this work we show that the MuSIC with a TeV-scale muon beam offers also a unique opportunity to probe New Physics. In particular, the relevant searches have the potential to surpass current experimental limits and explore new regimes of the parameter space for a variety of Beyond the Standard Model scenarios including: lepton-flavor violating leptoquarks, muonphilic vector boson interactions, axion-like particles coupling to photons, and heavy sterile neutrinos. Depending on the particular case, the sensitivity of the searches in the MuSIC may span a wide range of energy scales, namely from sub-GeV particles to the few TeV New Physics mediators. Our analysis demonstrates that the MuSIC can strike a powerful chord in the search for New Physics, thanks to unique combination of features that amplify its capabilities.

The energy created in deuterium-tritium fusion reactors originates from a high-intensity neutron flux interacting with the reactor's inner walls. The neutron flux can also be used to produce a self-sustaining reaction by lining the walls with lithium-rich `breeding blankets', in which a fraction of neutrons interacts with lithium, creating the tritium fuel. The high-intensity neutron flux can also result in the production of dark sector particles, feebly interacting light scalars or pseudoscalars, via nuclear transitions within the breeding blanket. We estimate the potential size of such dark sector flux outside the reactor, taking into account all current constraints, and consider possible detection methods at current and future thermonuclear fusion reactors. As a by-product, we also recast the SNO axion bound for a CP even scalar. We find that year-long searches at current and future reactors can set leading constraints on dark scalar -- and dark pseudoscalar -- nucleon couplings.