Left-Right Symmetric Models at the High-Intensity Frontier
Oscar Castillo-Felisola, Claudio O. Dib, Juan C. Helo, Sergey G. Kovalenko, Sebastian E. Ortiz
备注：
5 pages, 5 figures. RevTeX format. V2: Some figures and explanations improved, references added. Conclusions unchanged. V3: Minor grammatical improvements, version accepted for publication in PRD
We study constraints on Left-Right Symmetric models from searches of semileptonic decays of $D$, $D_{s}$, $B$ mesons, mediated by heavy neutrinos $N$ with masses $m_N\sim $ GeV that go on their mass shell leading to a resonant enhancement of the rates. Using these processes we examine, as a function of $m_N$ and $M_{W_R}$, the physics reach of the recently proposed high-intensity beam dump experiment SHiP, which is expected to produce a large sample of $D_s$ mesons. We compare these results with the corresponding reach of neutrinoless double beta decay experiments, as well as like-sign dilepton searches with displaced vertices at the LHC. We conclude that the SHiP experiment has clear advantages in probing the Left-Right Symmetric models for heavy neutrinos in the GeV mass range.
Massive neutrinos and leptonic mixings have provided the first evidence of flavour violation in the lepton sector, opening a unique gateway to many new phenomena. Among the latter, one finds processes violating lepton number, charged lepton flavours, or even the universality of lepton flavours. These very rare transitions can be studied in high-intensity facilities, and if observed, constitute a clear sign of New Physics. After a brief review of the experimental status of dedicated searches, we comment on the prospects of several well-motivated models of neutrino mass generation to several of …
We have calculated cross sections for the production of lepton pairs by a neutrino incident on a nucleus using both the equivalent photon approximation, and deep inelastic formalism. We find that production of mixed flavour lepton pairs can have production cross sections as high as 35 times those of the traditional muon pair-production process. Rates are estimated for the SHiP and DUNE intensity frontier experiments. We find that multiple trident production modes, some of which have never been observed, represent observable signals over the lifetime of the detectors. Our estimates indicate tha…
In recent years, a number of intensity-frontier experiments have been proposed to search for feebly interacting particles with a mass in the GeV range. We show analytically how the characteristic shape of the sensitivity regions of such experiments - upper and lower boundaries of the probed region, the maximal mass reach - depends on the parameters of the experiments, taking the SHiP and the MATHUSLA experiments as an example. We find a good agreement of our estimates with the results of the Monte Carlo simulations.
We show that when a dark abelian gauge sector and SU$(2)_{L}$ kinetically mix it necessarily generates a relation between the kinetic mixing strength and the mass of the mediating particle. Remarkably, this correspondence maps the weak scale directly to the kinetic mixing strengths being probed by modern fixed-target experiments and next generation flavor factories. This illuminates the exciting possibility of correlated discoveries of a new particle at the LHC and a dark photon at intensity frontier experiments. To motivate the scenario, we construct a simple model and explore its phenomenolo…
We discuss how the intensity and the energy frontiers provide complementary constraints within a minimal model of neutrino mass involving just one new field beyond the Standard Model at accessible energy, namely a doubly charged scalar $S^{++}$ and its antiparticle $S^{--}$. In particular we focus on the complementarity between high-energy LHC searches and low-energy probes such as lepton flavor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other.
This is the report of the Computing Frontier working group on Lattice Field Theory prepared for the proceedings of the 2013 Community Summer Study ("Snowmass"). We present the future computing needs and plans of the U.S. lattice gauge theory community and argue that continued support of the U.S. (and worldwide) lattice-QCD effort is essential to fully capitalize on the enormous investment in the high-energy physics experimental program. We first summarize the dramatic progress of numerical lattice-QCD simulations in the past decade, with some emphasis on calculations carried out under the ausp…
Despite the undeniable success of the Standard Model of particle physics (SM) there are some phenomena (neutrino oscillations, baryon asymmetry of the Universe, dark matter, etc.) that SM cannot explain. These phenomena indicate that the SM has to be modified. Most likely there are new particles beyond the SM. There are many experiments to search for new physics that can be divided into two types: energy and intensity frontier. In experiments of the first type, one tries to directly produce and detect new heavy particles. In experiments of the second type, one tries to directly produce and det…
We discuss ways to probe the origin of neutrino masses at the Energy and Intensity frontiers, in TeV-scale left-right seesaw models where small neutrino masses arise via type-I seesaw mechanism. We consider generic ('vanilla') version of such models as well as a version which leads to 'large' light-heavy neutrino mixing while keeping the neutrino masses small in a natural manner. We point out specific observable implications of these classes of models at the LHC as well as in searches for lepton flavor violating processes such as $μ\to eγ$ and $μ\to 3e$, and also in searches for lepton number …
In this Snowmass whitepaper, we describe the impact of ongoing and proposed intensity frontier experiments on the parameter space of the Minimally Supersymmetric Standard Model (MSSM). We extend a set of phenomenological MSSM (pMSSM) models to include non-zero CP-violating phases and study the sensitivity of various flavor observables in these scenarios Future electric dipole moment and rare meson decay experiments can have a strong impact on the viability of these models that is relatively independent of the detailed superpartner spectrum. In particular, we find that these experiments have th…
Dark matter particles can be observably produced at intensity-frontier experiments, and opportunities in the next decade will explore important parameter space motivated by thermal DM models, the dark sector paradigm, and anomalies in data. This whitepaper describes the motivations, detection strategies, prospects and challenges for such searches, as well as synergies and complementarity both within RF6 and across HEP.
These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 2, on the Intensity Frontier, discusses the program of research with high-intensity beams and rare processes. This area includes experiments on neutrinos, proton decay, charged-lepton and quark weak interactions, atomic and nuclear probes of fundamental symmetries, and searches for new, light, weakly-interacting particles.
Discovery Prospects for a Minimal Dark Matter Model at Cosmic and Intensity Frontier Experiments
Massachusetts Institute of Technology（麻省理工学院）；University of California Santa Cruz（加州大学圣克鲁兹分校）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
The tremendous progress in high-intensity laser technology and the establishment of dedicated high-field laboratories in recent years have paved the way towards a first observation of quantum vacuum nonlinearities at the high-intensity frontier. We advocate a particularly prospective scenario, where three synchronized high-intensity laser pulses are brought into collision, giving rise to signal photons, whose frequency and propagation direction differ from the driving laser pulses, thus providing various means to achieve an excellent signal to background separation. Based on the theoretical co…
In this Snowmass White Paper, we discuss physics opportunities involving heavy quarkonia at the intensity and energy frontiers of high energy physics. We focus primarily on two specific aspects of quarkonium physics for which significant advances can be expected from experiments at both frontiers. The first aspect is the spectroscopy of charmonium and bottomonium states above the open-heavy-flavor thresholds. Experiments at e^+ e^- colliders and at hadron colliders have discovered many new, unexpected quarkonium states in the last 10 years. Many of these states are surprisingly narrow, and som…
A staged approach towards muon based facilities for Intensity and Energy Frontier science, building upon existing and proposed facilities at Fermilab, is presented. At each stage, a facility exploring new physics also provides an R&D platform to validate the technology needed for subsequent stages. The envisioned program begins with nuSTORM, a sensitive sterile neutrino search which also provides precision neutrino cross-section measurements while developing the technology of using and cooling muons. A staged Neutrino Factory based upon Project X, sending beams towards the Sanford Underground …
A strongly interacting massive particle (SIMP) is an interesting candidate for dark matter (DM) because its self-interaction cross section can be naturally strong enough to address the astrophysical problem of small-scale structure formation. A simple model was proposed by assuming a monopole condensation, where composite SIMP comes from a "strongly interacting" U(1)$_{\rm d}$ gauge theory. In the original model, the DM relic abundance is determined by the $3\to2$ annihilation process via the Wess-Zumino-Witten term. In this letter, we discuss that the DM relic abundance is naturally determine…
Our goal is to study optical signatures of quantum vacuum nonlinearities in strong macroscopic electromagnetic fields provided by high-intensity laser beams. The vacuum emission scheme is perfectly suited for this task as it naturally distinguishes between incident laser beams, described as classical electromagnetic fields driving the effect, and emitted signal photons encoding the signature of quantum vacuum nonlinearity. Using the Heisenberg-Euler effective action, our approach allows for a reliable study of photonic signatures of QED vacuum nonlinearity in the parameter regimes accessible b…
We study hidden sector and long-lived particles at past (CHARM and NuCal), present (NA62 and SeaQuest/DarkQuest), and future (LongQuest) experiments that are at the high-energy frontier of the intensity frontier. We focus on exploring the minimal vector portal and variere-lifetime particles (VLP). VLP models have mostly been devised to explain experimental anomalies while avoiding existing constraints, and we demonstrate that proton fixed-target experiments provide one of the most powerful probes for the sub-GeV to few GeV mass range of the VLP models, using inelastic dark matter (iDM) as an e…
The search for new physics with long-lived particles is an ongoing and thriving effort in the High Energy Physics community which necessitates new search strategies such as novel algorithms, novel detectors, etc...For these reasons, one could perhaps add another frontier, the Lifetime Frontier, to the standard three (Energy, Intensity and Cosmic). In this talk, I will describe a BSM physics model whose characteristic signatures are decays of new (mirror) fermions at displaced vertices, a domain belonging to the Lifetime Frontier. It is a model of {\em non-sterile} right-handed neutrinos whose …
Is Dark Matter part of a Dark Sector? The possibility of a dark sector neutral under Standard Model (SM) forces furnishes an attractive explanation for the existence of Dark Matter (DM), and is a compelling new-physics direction to explore in its own right, with potential relevance to fundamental questions as varied as neutrino masses, the hierarchy problem, and the Universe's matter-antimatter asymmetry. Because dark sectors are generically weakly coupled to ordinary matter, and because they can naturally have MeV-to-GeV masses and respect the symmetries of the SM, they are only mildly constr…
Over the last Century the method of particle acceleration to high energies has become the prime approach to explore the fundamental nature of matter in laboratory. It appears that the latest search of the contemporary accelerator based on the colliders shows a sign of saturation (or at least a slow-down) in increasing its energy and other necessary parameters to extend this frontier. We suggest two pronged approach enabled by the recent progress in high intensity lasers.
Despite the undeniable success of the Standard Model of particle physics (SM), there are some phenomena that the SM can't explain. These phenomena indicate that the SM has to be modified. One of the possible ways to extend the SM is to introduce heavy neutral leptons (HNLs). To search for HNLs in intensity frontier experiments, one has to consider HNL production both in 2-body and 3-body decays of some mesons. We verified the possibility of using the parton level PYTHIA default matrix elements (without the form-factor formalism) to calculate HNL production in 3-body semileptonic decays of $B$ …
Present and prospective fundamental symmetry tests with nucleons, nuclei and atoms are probing for possible new physics at the TeV scale and beyond. These ongoing and proposed table-top as well as accelerator-based experiments are thus a vital component of the Intensity Frontier. At the same time, these tests provide increasingly sophisticated probes of long-distance strong interactions that are responsible for the structure of nucleons and nuclei. In this community report, some of the most compelling opportunities with nucleons, nuclei and atoms are summarized, drawing largely on input receiv…
If future neutrino oscillation experiments show that the neutrino mass spectrum is with normal ordering, m1 < m2 < m3, and the searches for neutrinoless double beta-decay with sensitivity to values of the effective Majorana mass |<m>| > 0.01 eV give negative results, the next frontier in the quest for neutrinoless double beta-decay will correspond to |<m>| ~ 0.001 eV. Assuming that massive neutrinos are Majorana particles and their exchange is the dominant mechanism generating neutrinoless double beta-decay, we analise the conditions under which |<m>|, in the case of three neutrino mixing and …
Most ongoing supersymmetry searches have concentrated on the high-energy frontier. High-intensity fixed target beamlines, however, offer an opportunity to search for supersymmetric particles with long lifetimes and low cross-sections in regions complementary to the ones accessible to collider experiments. In this paper, we consider R-parity violating supersymmetry searches for the lightest neutralino and use the NuTeV experiment as an example for the experimental sensitivity which can be achieved.
New Physics models in which the Standard Model particle content is enlarged via the addition of sterile fermions remain among the most minimal and yet most appealing constructions, particularly since these states are present as building blocks of numerous mechanisms of neutrino mass generation. Should the new sterile states have non-negligible mixings to the active (light) neutrinos, and if they are not excessively heavy, one expects important contributions to numerous high-intensity observables, among them charged lepton flavour violating muon decays and transitions, and lepton electric dipol…
The left-right symmetric model (LRSM) is a well-motivated framework to restore parity and implement seesaw mechanisms for the tiny neutrino masses at or above the TeV-scale, and has a very rich phenomenology at both the high-energy and high-precision frontiers. In this paper we examine the phase transition and resultant gravitational waves (GWs) in the minimal version of LRSM. Taking into account all the theoretical and experimental constraints on LRSM, we identify the parameter regions with strong first-order phase transition and detectable GWs in the future experiments. It turns out in a siz…
Although searches for new physics at the CERN Large Hadron Collider will probably dominate the the agenda of the experimental high energy physics community during the next decade or more, high-intensity experiments at the tau-charm and beauty thresholds will continue to play important complementary roles. These include the establishment of stringent constraints on proposed theories for beyond-the-Standard-Model physics and unique opportunities to address some new physics scenarios that are inaccessible at the LHC. In addition, in the event that the LHC does discover some new phenomena, high se…
We show that the longitudinal beam polarization option at a future electron-positron collider provides an unambiguous distinction between low-scale seesaw models of neutrino mass. This is possible due to the fact that the pair production cross section of the heavy neutrinos in seesaw models is sensitive to the polarization of the initial lepton beams, and for a suitable choice of the polarization, shows a clear enhancement over the unpolarized cross section. More interestingly, the choice of the beam polarization for which the enhancement is maximum is governed by the size of the light-heavy n…
The decays $B_d^0\to J/ψK^0_{\text{S}}$and $B_s^0\to J/ψϕ$ play a key role for the determination of the $B^0_q$-$\bar B^0_q$ ($q=d,s$) mixing phases $ϕ_d$ and $ϕ_s$, respectively. The theoretical precision of the extraction of these quantities is limited by doubly Cabibbo-suppressed penguin topologies, which can be included through control channels by means of the $SU(3)$ flavour symmetry of strong interactions. Using the currently available data and a new simultaneous analysis, we discuss the state-of-the-art picture of these effects and include them in the extracted $ϕ_q$ values. We have a c…
The mediators of neutrino mass generation can provide a probe of neutrino properties at the next round of high-energy hadron (FCC-hh) and lepton colliders (FCC-ee/ILC/CEPC/CLIC). We show how the decays of the Higgs triplet scalars mediating the simplest seesaw mechanism can shed light on the neutrino mass scale and mass-ordering, as well as the atmospheric octant. Four-lepton signatures at the high-energy frontier may provide the discovery-site for charged lepton flavour non-conservation in nature, rather than low-energy intensity frontier experiments.
Inspired by the potential prospects of high-luminosity dedicated colliders and the high enthusiasms in searching for new physics in the flavor sector at the intensity frontier, the $Υ(1S)$ ${\to}$ $D^{-}π^{+}$, $\overline{D}^{0}π^{0}$ and $D_{s}^{-}K^{+}$ weak decays are studied with the perturbative QCD approach. It is found within the standard model that the branching ratios for the concerned processes are tiny, about ${\cal O}(10^{-18})$, and far beyond the detective ability of current experiments unless there exists some significant enhancements from a noval interaction.
Collider signals of dark photons are an exciting probe for new gauge forces and are characterized by events with boosted lepton jets. Existing techniques are efficient in searching for muonic lepton jets but due to substantial backgrounds have difficulty constraining lepton jets containing only electrons. This is unfortunate since upcoming intensity frontier experiments are sensitive to dark photon masses which only allow electron decays. Analyzing a recently proposed model of kinetic mixing, with new scalar particles decaying into dark photons, we find that existing techniques for electron je…
We point out that in the minimal left-right realization of TeV scale seesaw for neutrino masses, the neutral scalar from the right-handed $SU(2)_R$ breaking sector could be much lighter than the right-handed scale. We discuss for the first time the constraints on this particle from low-energy flavor observables, find that the light scalar is necessarily long-lived. We show that it can be searched for at the LHC via displaced signals of a collimated photon jet, and can also be tested in current and future high-intensity experiments. In contrast to the unique diphoton signal (and associated jets…
We study vacuum birefringence and x-ray photon scattering in the head-on collision of x-ray free electron and high-intensity laser pulses. Resorting to analytical approximations for the numbers of attainable signal photons, we analyze the behavior of the phenomenon under the variation of various experimental key-parameters and provide new analytical scalings. Our optimized approximations allow for quantitatively accurate results on the one-percent level. We in particular demonstrate that an appropriate choice of the x-ray focus and pulse duration can significantly improve the signal for given …
We constrain the lifetime of thermally produced Heavy Neutral Leptons (HNLs) from primordial nucleosynthesis. We show that even a small fraction of mesons present in the primordial plasma leads to the over-production of the primordial helium. This puts an upper bound on the lifetime of HNLs $τ_{N}<0.02$ s for masses $m_{N}>m_π$ (as compared to 0.1 s reported previously). In combination with accelerator searches, this allows us to put a new lower bound on the HNLs masses and defining the "bottom line" for HNL searches at the future Intensity Frontier experiments.
This report was prepared on behalf of three Energy Frontier Topical Groups of the Snowmass 2021 Community Planning Exercise. It summarizes the status and implications of studies of strong interactions in high-energy experiments and QCD theory. We emphasize the rich landscape and broad impact of these studies in the decade ahead. Hadronic interactions play a central role in the high-luminosity Large Hadron Collider (LHC) physics program, and strong synergies exist between the (HL-)LHC and planned or proposed experiments at the U.S. Electron-Ion Collider, CERN forward physics experiments, high-i…
