Crossroads between Theory and Phenomenology

Jun 10, 2024, 8:30 AM → Jun 28, 2024, 7:00 PM Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Gian Giudice (CERN), Gilly Elor, Hyung Do Kim (Seoul National University (KR)), Matthew Philip Mccullough (CERN), Minho SON, Sungwoo Hong, Tim Cohen (CERN)

A three-week CERN-CKC TH Institute on BSM physics with a light schedule intended to maximally facilitate scientific interaction and collaboration.

The BSM programme will broadly, but not strictly, be thematically organised by topic; the first week linking to cosmology, the second to model building and high energy, and the final week focussing on the interface with formal phenomenology.

Registrations are now closed. Invited participants who still wish to apply should contact the organisers directly.

Week 1 Photo here!

Week 2 Photo here!  More week 2 photos here and here!

Monday, June 10

1 Welcome

Speaker: Matthew Philip Mccullough (CERN)

THInstitute.pdf

2 Shining axions through astrophysical walls

Speaker: Benjamin Safdi

CERN_Safdi_indico.key

CERN_Safdi_indico.pdf

10:45 AM Coffee

3 More Axion Stars from Strings

We show that if dark matter consists of QCD axions in the post-inflationary scenario more than ten percent of it efficiently collapses into Bose stars at matter-radiation equality. Such a result is mostly independent of the present uncertainties on the axion mass. This large population of solitons, with asteroid masses and Earth-Moon distance sizes, might plausibly survive until today, with potentially interesting implications for phenomenology and experimental searches.

Speaker: Marco Gorghetto (DESY)

crossroads_Gorghetto.pdf

1:30 PM Coffee

6:00 PM Unsponsored gathering

Tuesday, June 11

4 Gravitational Wave-Induced Freeze-In of Fermionic Dark Matter

Speaker: Azadeh Maleknejad

CERN.pdf

10:45 AM Coffee

5 Where to Look and How to Look for High-Frequency Gravitational Waves

Abstract: Stochastic backgrounds of gravitational waves can potentially open a window on extremely high energies, giving us information on phase transitions at the GUT scale and many other BSM phenomena. In this talk I will discuss simple heuristic arguments that allow to establish the smallest detectable energy density in a primordial gravitational wave background. I will focus mainly on what is achievable with realistic detectors, and comment on the potential of advanced quantum sensing techniques. In the foreseeable future, it is not feasible to go beyond the BBN bound for frequencies above 100 kHz.

Speaker: Raffaele D'Agnolo (CEA IPhT Saclay)

dagnolo_CERN.pdf

1:30 PM Coffee

6 Stability of Superconducting Strings

Speaker: Wei Xue (University of Florida (US))

Wednesday, June 12

7 Simulating Stochastic Gravitational Waves from Early Structure Formation

Gravitational wave detectors provide a chance to observe the state of the very early universe and have important sensitivities for studies of early universe cosmology and searches for physics beyond the Standard Model. In this talk, I will discuss the production of potentially detectable stochastic gravitational wave backgrounds in early matter dominated eras in the linear and nonlinear regimes of structure formation.

Speaker: Joshua Foster (Massachusetts Institute of Technology)

SGWB.key

10:45 AM Coffee

8 The Strong CP Problem in String Theory (Cosmo+Swampland meeting)

Speaker: Jakob Ulrich Moritz

1:30 PM Coffee

9 TH colloquium by Krishna Rajagopal, "Novel Probes of the Primordial Liquid"

Please check details on https://indico.cern.ch/event/1384507/

Thursday, June 13

10 QCD axion strings or seeds?

Speaker: Dr Simone Blasi (DESY)

crossroads talk.pdf

10:45 AM Coffee

11 Dynamical Generation of the Baryon Asymmetry from a Scale Hierarchy

Abstract: We propose a novel baryogenesis scenario where the baryon asymmetry originates directly from a hierarchy between two fundamental mass scales: the electroweak scale and the Planck scale. Our model is based on the neutrino-portal Affleck-Dine (AD) mechanism, which generates the asymmetry of the AD sector during the radiation-dominated era and subsequently transfers it to the baryon number before the electroweak phase transition. The observed baryon asymmetry is then a natural outcome of this scenario. The model is testable as it predicts the existence of a Majoron with a keV mass and an electroweak scale decay constant. The impact of the relic Majoron on ΔNeff can be measured through near-future CMB observations.

Speaker: Jae Hyeok Chang (Fermilab and UIC)

Slides_Chang.pdf

1:30 PM Coffee

12 Cosmological Production of ROMP Dark Matter

Rapidly Oscillating Massive Particles (ROMPs) arise in quantum systems with non-diagonal interaction mass matrices. This misalignment between flavor and mass eigenstates leads to oscillations such as those between electron and muon neutrinos in the Standard Model, or between active and sterile neutrinos in Beyond the Standard Model frameworks to name just a few examples. In this talk, I will discuss the general framework for dark matter production via oscillations. I will focus on ROMP systems where one flavor state, chi, is weakly coupled to the Standard Model (and hence a good dark matter candidate) and the second flavor state, psi, is strongly coupled to the Standard Model such that psi oscillations to chi in the early universe can efficiently produce chi as the dark matter. I will discuss how oscillations, scatterings, thermal masses, and resonances all play a role to give ROMPs a rich cosmology.

Speaker: David Dunsky

CERN_ROMPs.key

Friday, June 14

13 Axion dark matter from kinetic misalignment

Kinetic misalignment enables axion DM at low axion axion decay constant, which is particularly relevant for the whole experimental programme af axion searches. I’ll discuss its distinctive features such as axion fragmentation and its signatures, as well as
UV implementations of rotating axions.

Speaker: Geraldine Servant (Deutsches Elektronen-Synchrotron (DE))

Servant-CERN-TH-Institute-2024.pdf

10:45 AM Coffee

14 Probing the dark sector with Large Scale Structure

Speaker: Ennio Salvioni (University of Sussex (GB))

Talk_CERN_upload.pdf

1:30 PM Coffee

5:00 PM Unsponsored Gathering in R1 OR Beach Party

There are two options to choose from.

A) Hanging out in R1 from 17:00 to continue the discussions, as on Monday evening.

OR

B) Joining in with the CERN-TH gathering from 17:30 at the UN beach. Some relevant information:

Directions: This is the Google Location-link: https://www.google.com/maps/place/UN+Port+beach+club/@46.2266307,6.1488917,15z/data=!4m2!3m1!1s0x0:0xd2c75ea4315d506d?sa=X&ved=1t:2428&ictx=111

The webpage of the UN beach is https://www.unport.org/. Perhaps the simplest way to get there from CERN on a Friday afternoon is by tram+bus. The bike parking will be busy but it should be OK.

Amenities: There is a beach, changing rooms, a restaurant, and a bar. One can swim there and buy food and drinks. We believe the restaurant will close around 22. Importantly, note that one can bring their own food and beverages into the UN beach. So feel free to do as you prefer.

Events on that day: It seems that they will broadcast the Germany-Scotland EuroCup match at 21, and they will also have a dancing class, as well as a DJ with music until 2 am.

Entrance and accompanying people — Families and partners are of course welcome to the party. Simply note that in order to enter you will need to show your CERN access card. That will allow you to enter together with at most 4 extra people (that do not need to have one). Note that entering costs 5 CHF per person (and needs to be paid by card).

The beach area is a mix of grass and earth, so we would recommend not wearing your newest shoes to the party =).

Monday, June 17

10:45 AM Coffee

15 Welcome

Speaker: Matthew Philip Mccullough (CERN)

THInstitute.pdf

16 Shadow Matter

I will argue that there are quantum states of the field theories of general relativity and electromagnetism that we typically ignore, but have interesting phenomenological effects. These states amount to loosening the constraint equations known as the Hamiltonian and momentum constraints in GR and Gauss’ law in EM. Turning off the Hamiltonian constraint sources non-dynamical parts of the metric which mimic a pressureless dust, and thus these effects may be the explanation as to why we have inferred the existence of dark matter, both locally and cosmologically. Turning off the momentum constraints add additional velocity-dependent source terms to this effective dust, but these effects are not conserved and redshift quickly outside the horizon. Turning off the Gauss’ law constraint mimics a charge density that does not respond to electric forces, but follows geodesics, thus adding a charged component to the dust. If this new structure in the gravitational and electric fields explain dark matter, it forbids an early period of inflation and therefore requires a different explanation for density perturbations.

Speaker: David Kaplan

Shadow Matter -- Kaplan.pdf

1:30 PM Coffee

17 Continuous-Spin Particles, On Shell

Speaker: Brando Bellazzini

CSP_Cern_Bellazzini.pdf

5:00 PM Unsponsored gathering

Tuesday, June 18

18 n-shell relations between effective field theories of gluons

It is known that universal algebraic structures govern the scattering amplitudes of a large web of theories, whose boundaries are however not well understood. In this talk, I will comment on effective field theory deformations of this web. Focussing on tree-level dynamics, I will explain that the scattering amplitudes of gluons minimally coupled to adjoint scalars contain all of the information required to construct those of a tower of gluon EFTs. For instance, I will present closed-form expressions for all-multiplicity scattering amplitudes in the (CP-even) EFT of gluons at mass dimension six, and for a specific choice of Wilson coefficients at dimension eight — all constructed through a systematic and explicit recycling of dimension-four data. I will also mention how one can recursively turn spacetime dimensions into operator dimensions. The technique behind those results is our extension of the so-called covariant color-kinematics duality introduced by Cheung and Mangan.

Speaker: Quentin Bonnefoy (DESY)

10:45 AM Coffee

19 Vignettes from Strongly-Coupled Dark Sectors

I’ll discuss three recent developments related to dark glueball, dark meson, and dark baryon theory and phenomenology. Along the way we’ll see the continued importance of prompt and long-lived searches at LHC, as well as a surprising symmetry impacting dark baryon direct detection that appears in a broad class of strongly-coupled dark sectors.

Speaker: Graham Kribs

cern_strongly_coupled_2024_06.pdf

1:30 PM Coffee

20 Learning new tricks with the Higgs?

Speakers: Christoph Englert, Christoph Peter Englert (University of Glasgow (GB))

2024_CERN.pdf

Wednesday, June 19

21 A different view on colliders

Energy correlators do live at the crossroads between theory and phenomenology. I will briefly review developments on both fronts that explain the resurgence of interest on these old observables. Then, I present how to compute high point correlators from recursion relations, what can be learned from low point ones, and how to go beyond energies.

Speaker: Mr Marc Riembau (CERN)

10:45 AM Coffee

22 Higgs Shift-Symmetries

Speaker: Javi Serra (IFT)

23 New physics on the run from precision tests - TH colloquium

Speaker: Sophie Alice Renner (University of Glasgow (GB))

TH colloquium.pdf

3:00 PM Coffee

Thursday, June 20

24 Non-decoupling new particles

Speaker: David Sutherland

Talk.pdf

10:45 AM Coffee

25 Probing ultralight dark matter with gravity wave detectors

Speaker: Hyungjin Kim

Kim_CERN_June2024.pdf

1:30 PM Coffee

26 Matching EFT to LHC

Speaker: Markus Luty (University of California Davis)

24_06_20 CERN.pdf

Friday, June 21

27 Non-invertible Naturalness and Quantum Flavodynamics

Speaker: Seth Koren (University of Notre Dame)

NoninvertibleNaturalness.pdf

10:45 AM Coffee

28 Strong gauge dynamics and BSM model building tools

Many attractive ideas on BSM physics involve strong gauge dynamics we do not understand well. I present recent attempts to gain better understanding of strong gauge dynamics using supersymmetry and anomaly mediation of supersymmetry breaking. Then I speculate on areas of BSM model building that they may open up.

Speaker: Hitoshi Murayama (University of California Berkeley (US))

1:30 PM Coffee

5:00 PM Unsponsored gathering

Monday, June 24

10:45 AM Coffee

29 Welcome

Speaker: Tim Cohen (CERN)

THInstitute.pdf

30 Talk

Speaker: T. Daniel Brennan

1:30 PM Coffee

31 Particle Physics meets Gravitational Wave Physics

I will give an overview of how quantum field theory—the main tool of particle physics—is applied to the study of relativistic two-body problem, how it is relevant to precision measurements in future gravitational wave observatories, and how it connects to my research in this topic; the effects of spin in binary dynamics.

Speaker: Mr Jung-Wook Kim

PP_meets_GWP_public.pdf

5:00 PM Unsponsored gathering

Tuesday, June 25

32 A holographic view of the QCD axion

Speaker: Tony Gherghetta

HolographicAxion.pdf

10:45 AM Coffee

33 Axion couplings as UV probes

Speaker: Michael Nee (Harvard University)

Axion couplings as UV probes.pdf

1:30 PM Coffee

34 Geometry of Scattering Amplitudes

Speaker: Andreas Helset (CERN)

Geometry_Amplitudes.pdf

Wednesday, June 26

35 Hamiltonian Truncation and Effective Field Theory

Speaker: Kara Michelle Farnsworth (Universite de Geneve (CH))

Crossroads_Farnsworth.pdf

10:45 AM Coffee

36 On-shell techniques for the standard-model effective theory

Speaker: Gauthier Durieux (CP3 - UCLouvain)

durieux-2024-06-26-cern.pdf

1:30 PM Coffee

37 Thinking Outside the Hypercube: RS and its Implications - TH colloquium

Speaker: lisa randall (harvard)

Thursday, June 27

38 Gravitational waves from domain walls bounded by inflated cosmic strings

Speaker: Liantao Wang

GW_CERN.pdf

10:45 AM Coffee

39 The quantum width of a causal diamond

Speaker: Kathryn Zurek (Caltech)

1:30 PM Coffee

40 Topological Portal to the Dark Sector: from EFT to UV

Speaker: Joseph Enea Davighi

Topological Portal to the Dark Sector.pdf

Friday, June 28

41 SU(N) and O(N) Representation Theory at non-integer N

The standard representation theory for SU(N) and O(N) groups are defined at positive integer N. However, cases of non-integer N are often encountered, e.g. when studying dimensional regularization, evanescent operators, conformal bootstrap, etc. A natural continuation to non-integer N (such as N=3.99) is to take the one at infinitely large integer N. This contains representations with arbitrarily high ranks, which must appear ("specialize") as representations with valid ranks when N is taken to be an integer. This specialization map is complicated to work out for the O(N) group. In this talk, I will introduce a very efficient new algorithm through clipping the Young diagram. I also clarify that the Racah-Speiser algorithm in textbooks is for a completely different task, which cannot achieve what our new algorithm does.

Speaker: Xiaochuan Lu (University of California, San Diego)

Lu_Clipping_2024-06-28.pdf

10:45 AM Coffee

42 Abelian Instantons and Monopole Scattering

It is usually assumed that 4D instantons can only arise in non-Abelian theories. In our recent work arXiv:2406.13738, we re-examine this conventional wisdom by explicitly constructing instantons in an Abelian gauge theory: $QED_4$ with $N_f$ flavors of Dirac fermions, in the background of a Dirac monopole. This is the low-energy effective field theory for fermions interacting with a 't Hooft-Polyakov monopole, in the limit where the monopole is infinitely heavy (hence pointlike) and static. This theory, whose non-topological sectors were studied by Rubakov and Callan, has a far richer structure than previously explored. We show how to calculate the topological instanton number, demonstrate the existence of 't Hooft zero modes localized around such instantons, and show how instantons in the path integral provide the underlying mechanism for the Callan-Rubakov process: monopole-catalyzed baryon decay with a cross-section that saturates the unitarity bound. Our computation relies on correctly identifying the relevant EFT for monopole catalysis as axial $QED_2$ in an effective $AdS_2$ metric.

Speaker: Ofri Telem (The Hebrew University of Jerusalem)

4912_001.pdf

1:30 PM Coffee

5:00 PM Unsponsored gathering