About

Maxim Perelstein is a Professor in the Department of Physics at Cornell University, with a background that includes a B.S. in Physics from the Moscow Institute for Physics and Technology, an M.S. from UCLA, and a Ph.D. from Stanford University. His research primarily focuses on the theory and phenomenology of electroweak symmetry breaking (EWSB), exploring mechanisms responsible for this fundamental process in the standard model of particle physics. He is interested in constructing new models of EWSB and devising strategies for their experimental testing, particularly in relation to experiments at the Large Hadron Collider (LHC). His recent work includes studying predictions of natural EWSB models for the properties of the Higgs boson, proposing novel search strategies for supersymmetry and other new physics, and analyzing collider data to understand the early Universe's electroweak phase transition. Additionally, Perelstein's research extends into theoretical cosmology, focusing on models of dark energy, dark matter, and inflation, including the proposal of a new dark matter candidate called Elastically Decoupling Relic (ELDER). His academic journey includes positions as a Visiting Postdoctoral Fellow at Lawrence Berkeley National Laboratory, Assistant, Associate, and then Professor at Cornell University, with notable awards such as the NSF Career Award and a Simons Fellowship in Theoretical Physics.

Research topics

• Political Science
• Computer Science
• Database
• Nuclear physics
• Physics
• Particle physics

Selected publications

• Conformal Freeze-in dark matter: 5D dual and phase transition

  Journal of High Energy Physics · 2025-06-13

  articleOpen accessSenior author

  A bstract Conformal Freeze-in (COFI) scenario postulates a dark sector described by a conformal field theory (CFT) at energies above the “gap scale” in the keV – MeV range. At the gap scale, the dark CFT undergoes confinement, and one of the resulting bound states is identified as the dark matter candidate. In this paper, we study this model in the context of the AdS/CFT correspondence with a focus on the mechanism of the infrared (IR) breaking of conformal invariance in the dark sector. We construct the holographic dual to the conformal dark sector, given by a Randall-Sundrum-like model in 5D, where the Standard Model (SM) fields and the dark matter candidate are placed on the ultraviolet (UV) and IR branes respectively. The separation between the UV and IR branes is stabilized by a bulk scalar field, naturally generating a hierarchy between the electroweak scale and the gap scale. We find that the parameter space of COFI comprises two distinct branches of CFT’s living on the Anti-de-Sitter (AdS) boundary, each corresponding to a different UV boundary condition. The two branches of CFT’s result in different radion potentials. The confinement of the CFT is dual to the spontaneous symmetry breaking by the 5D radion potential. We then use this dual 5D setup to study the cosmological confining phase transition in the dark sector. We find the viable parameter space of the theory which allows the phase transition to complete promptly without significant supercooling.

  PublisherOA PDFDOI

• Conformal freeze-in from neutrino portal

  Journal of High Energy Physics · 2025-04-11 · 2 citations

  articleOpen access

  A bstract We study a scenario where a dark sector, described by a Conformal Field Theory (CFT), interacts with the Standard Model through the neutrino portal. In this setup, conformal invariance breaks below the electroweak scale, causing the theory to transition into a confined (hadronic) phase. One of the hadronic excitations in this phase can act as dark matter. In the “Conformal Freeze-In” cosmological framework, the dark sector is populated through interactions with the Standard Model at temperatures where it retains approximate conformal symmetry. The dark matter relic density depends on the CFT parameters, such as the dimension of the operator coupled to the Standard Model. We demonstrate that this model can reproduce the DM relic density and meet all observational constraints. The same neutrino portal interaction may also generate masses for the active neutrinos. The dark matter candidate could either be a pseudo-Goldstone boson (PGB) or a composite fermion with the quantum numbers of a sterile neutrino. In the latter case, the model is consistent with the current X-ray constraints, and may be detectable with future X-ray observations.

  PublisherOA PDFDOI

• Conformal Freeze-in Dark Matter: 5D Dual and Phase Transition

  ArXiv.org · 2025-02-10

  preprintOpen accessSenior author

  Conformal Freeze-in (COFI) scenario postulates a dark sector described by a conformal field theory (CFT) at energies above the ``gap scale" in the keV$-$MeV range. At the gap scale, the dark CFT undergoes confinement, and one of the resulting bound states is identified as the dark matter candidate. In this paper, we study this model in the context of the AdS/CFT correspondence with a focus on the mechanism of the infrared (IR) breaking of conformal invariance in the dark sector. We construct the holographic dual to the conformal dark sector, given by a Randall-Sundrum-like model in 5D, where the Standard Model (SM) fields and the dark matter candidate are placed on the ultraviolet (UV) and IR branes respectively. The separation between the UV and IR branes is stabilized by a bulk scalar field, naturally generating a hierarchy between the electroweak scale and the gap scale. We find that the parameter space of COFI comprises two distinct branches of CFT's living on the Anti-de-Sitter (AdS) boundary, each corresponding to a different UV boundary condition. The two branches of CFT's result in different radion potentials. The confinement of the CFT is dual to the spontaneous symmetry breaking by the 5D radion potential. We then use this dual 5D setup to study the cosmological confining phase transition in the dark sector. We find the viable parameter space of the theory which allows the phase transition to complete promptly without significant supercooling.

  PublisherOA PDFDOI

• Coherent Freeze-Out of Dark Matter

  Physical Review Letters · 2025-11-20

  articleOpen access

  We propose a novel coherent freeze-out mechanism where a weakly interacting massive particle (WIMP) is quadratically coupled to a light axionlike particle (ALP). Although the coupling is too feeble to thermalize the ALP, coherent forward scattering induces medium-dependent mass shifts that significantly modify both WIMP freeze-out and ALP misalignment dynamics. The symmetry of the ALP potential is broken at high temperatures and restored through either a first-order transition or a crossover. In the former, WIMPs alone compose dark matter with annihilation cross sections enhanced by up to 3 orders of magnitude relative to the standard scenario; in the latter, a Planck-suppressed coupling naturally yields an ALP abundance of the order of the observed dark matter density, largely independent of its initial displacement and mass.

  PublisherDOI

• Sommerfeld Enhancement from Quantum Forces for Dark Matter

  ArXiv.org · 2025-07-16

  preprintOpen access

  Quantum forces are long-range interactions that arise only at the loop level. In this work, we study the Sommerfeld enhancement of dark matter (DM) annihilation cross sections caused by quantum forces. One notable feature of quantum forces is that they are subject to coherent enhancement in the presence of a background of mediator particles, which occurs in many situations in cosmology. We show that this effect has important implications for the Sommerfeld enhancement and DM physics. For the first time, we calculate the Sommerfeld factor induced by quantum forces for both bosonic and fermionic mediators, including the background corrections. We observe several novel features of the Sommerfeld factor that do not exist in the case of the Yukawa potential, such as temperature-induced resonance peaks for massless mediators, and having both enhancement and suppression effects in the same model with different DM masses. As direct applications, we discuss the DM phenomenology affected by the Sommerfeld enhancement from quantum forces, including thermal freeze-out, CMB spectral distortion from DM annihilation, and DM indirect detection. We highlight one particularly interesting effect relevant to indirect detection caused by the Sommerfeld enhancement in a non-thermal background of bosonic mediators in the galaxy, in which case the DM mass is shifted due to the background correction and the effective cross section for DM annihilation can be either enhanced or suppressed. This may be important for DM searches in the Milky Way or its satellite galaxies.

  PublisherOA PDFDOI

• Collider Searches for Near-Continuum Dark Matter

  ArXiv.org · 2025-10-20

  preprintOpen access

  We study collider constraints on the near-continuum dark matter model, in which the dark sector consists of a tower of closely spaced states with weak-scale masses coupled to the Standard Model through a $Z$-portal. To capture this structure in a model-agnostic way, we introduce a minimal parameterization that encodes the dominant geometric information with three parameters. Using a custom-built Monte-Carlo tool for near-continuous spectra, we simulate DM-pair production at $\sqrt{s}=13$ TeV and subsequent cascade decays via on/off-shell $Z$ bosons, which yield events with large missing transverse momentum and high jet multiplicity. Recasting the CMS multijet$+H_T^{\rm miss}$ analysis of Run-2 data (35.9 fb$^{-1}$), we derive bounds on the model parameter space. Extrapolating these bounds, we provide High-Luminosity LHC projections (3 ab$^{-1}$). We also project sensitivities for future electron-positron colliders at $\sqrt{s}=365$ GeV and $\sqrt{s}=500$ GeV, showing substantial improvements over the HL-LHC. The current LHC sensitivity is beginning to approach the theoretically motivated region of the parameter space, while future colliders will be able to comprehensively test this model.

  PublisherOA PDFDOI

• Sommerfeld enhancement from quantum forces for dark matter

  Journal of High Energy Physics · 2025-12-11 · 1 citations

  articleOpen access

  A bstract Quantum forces are long-range interactions that arise only at the loop level. In this work, we study the Sommerfeld enhancement of dark matter (DM) annihilation cross sections caused by quantum forces. One notable feature of quantum forces is that they are subject to coherent enhancement in the presence of a background of mediator particles, which occurs in many situations in cosmology. We show that this effect has important implications for the Sommerfeld enhancement and DM physics. For the first time, we calculate the Sommerfeld factor induced by quantum forces for both bosonic and fermionic mediators, including the background corrections. We observe several novel features of the Sommerfeld factor that do not exist in the case of the Yukawa potential, such as temperature-induced resonance peaks for massless mediators, and having both enhancement and suppression effects in the same model with different DM masses. As direct applications, we discuss the DM phenomenology affected by the Sommerfeld enhancement from quantum forces, including thermal freeze-out, CMB spectral distortion from DM annihilation, and DM indirect detection. We highlight one particularly interesting effect relevant to indirect detection caused by the Sommerfeld enhancement in a non-thermal background of bosonic mediators in the galaxy, in which case the DM mass is shifted due to the background correction and the effective cross section for DM annihilation can be either enhanced or suppressed. This may be important for DM searches in the Milky Way or its satellite galaxies.

  PublisherOA PDFDOI

• Collider signatures of near-continuum dark matter

  Journal of High Energy Physics · 2024-05-17 · 2 citations

  articleOpen accessSenior author

  A bstract In this paper we study a near-continuum dark matter model, in which dark sector consists of a tower of closely spaced states with weak-scale masses. We construct a five-dimensional model which naturally realizes this spectrum. The dark matter is described by a bulk field, which interacts with the brane-localized Standard Model sector via a Z portal. We then study collider signatures of this model. Near-continuum dark matter states produced in a collider undergo cascade decays, resulting in events with high multiplicity of jets and leptons, large missing energy, and displaced vertices. A custom-built Monte Carlo tool described in this paper allows for detailed simulation of the signal events. We present results of such simulations for the case of electron-positron collisions.

  PublisherOA PDFDOI

• Anomaly detection in the presence of irrelevant features

  Journal of High Energy Physics · 2024-02-28 · 21 citations

  articleOpen accessCorresponding

  A bstract Experiments at particle colliders are the primary source of insight into physics at microscopic scales. Searches at these facilities often rely on optimization of analyses targeting specific models of new physics. Increasingly, however, data-driven model-agnostic approaches based on machine learning are also being explored. A major challenge is that such methods can be highly sensitive to the presence of many irrelevant features in the data. This paper presents Boosted Decision Tree (BDT)-based techniques to improve anomaly detection in the presence of many irrelevant features. First, a BDT classifier is shown to be more robust than neural networks for the Classification Without Labels approach to finding resonant excesses assuming independence of resonant and non-resonant observables. Next, a tree-based probability density estimator using copula transformations demonstrates significant stability and improved performance over normalizing flows as irrelevant features are added. The results make a compelling case for further development of tree-based algorithms for more robust resonant anomaly detection in high energy physics.

  PublisherOA PDFDOI

• Sub-GeV dark matter search at ILC beam dumps

  Journal of High Energy Physics · 2024-02-16 · 6 citations

  articleOpen access

  A bstract Light dark matter particles may be produced in electron and positron beam dumps of the International Linear Collider (ILC). We propose an experimental setup to search for such events, the Beam-Dump eXperiment at the ILC (ILC-BDX). The setup consists of a muon shield placed behind the beam dump, followed by a multi-layer tracker and an electromagnetic calorimeter. The calorimeter can detect electron recoils due to elastic scattering of dark matter particles produced in the dump, while the tracker is sensitive to decays of excited dark-sector states into the dark matter particle. We study the production, decay and scattering of sub-GeV dark matter particles in this setup in several models with a dark photon mediator. Taking into account beam-related backgrounds due to neutrinos produced in the beam dump as well as the cosmic-ray background, we evaluate the sensitivity reach of the ILC-BDX experiment. We find that the ILC-BDX will be able to probe interesting regions of the model parameter space and, in many cases, reach well below the relic target.

  PublisherOA PDFDOI

Recent grants

• CAREER: Theoretical Interpretation of the Large Hadron Collider Data

  NSF · $401k · 2009–2015

Frequent coauthors

• Michael E. Peskin

  26 shared

• Lance J. Dixon

  Imperial College London

  23 shared

• Seung J. Lee

  17 shared

• Christophe Grojean

  16 shared

• David C. Dunbar

  16 shared

• Jenny List

  Universität Hamburg

  15 shared

• Zackaria Chacko

  14 shared

• Mihoko M. Nojiri

  13 shared

Labs

• Cornell Particle TheoryPI

  Theoretical Particle Physics

Awards & honors

• NSF Career Award (2009-2013)
• Simons Fellow in Theoretical Physics (2016-2017)