The $ e^+e^- $ annihilation of unpolarized beams is free from initial hadron states or initial anisotropy around the azimuthal angle. Hence, it is ideal for studying the correlations of dynamical origin via final state jets. We investigate the planar properties of multi-jet events employing the relevant event-shape observables at next-to-next-to-leading order ( $ {\cal{O}} $ ( $ \alpha_{s}^{3} $ )) in perturbative Quantum Chromodynamics (QCD). In particular, the azimuthal angle correlations on the long pseudo-rapidity (polar angle) range (Ridge correlation) between the inclusive jet momenta are calculated. We demonstrate that the significant planar properties and the strong correlations as the consequence are natural results of the energy-momentum conservation of the perturbative QCD radiation dynamics. Our study provides benchmarks of a hard strong interaction background for investigating the collective and/or thermal effects via the Ridge-like correlation observables for various scattering processes.

China

Xuan Chen

Yuesheng Dai

Shi-Yuan Li

Zong-Guo Si

Huiting Sun

Planar property and long-range azimuthal correlation in $\textit{e}$ $^{+}$ $\textit{e}$ $^{–}$ annihilation * Supported by the National Science Foundation of China (NSFC) (12475085, 12275157, 12321005, 12235008)

Recently, the study of long-lived particles (LLPs) has attracted increasing attention. In this work, we analyze the full parameter space of the Type-I Two-Higgs-Doublet Model (2HDM) that allows for light long-lived scalar ($\textit{H}$) and pseudoscalar ($\textit{A}$) particles. When involving a light beyongd Standard Model (BSM) Higgs, the ∆$\textit{S}$ could be the main contribution during the global fit of the oblique parameters, which is different to ∆$\textit{T}$ being the main factor for heavy BSM Higgs cases. By imposing theoretical constraints such as vacuum stability and perturbative unitarity, together with current experimental bounds, we summarize a complete region for a potential light $\textit{H}$ with cos($\textit{β}$ − $\textit{α}$) ≃ $$ \frac{1}{\tan \beta } $$ , light $\textit{A}$ with cos($\textit{β}$ − $\textit{α}$) ≃ $$ \frac{1}{\tan \beta}\frac{2{m}_H^2-{m}_h^2}{m_H^2-{m}_h^2} $$ , and point out the invisible Higgs decay is the most important constraint. We further identify viable regions for LLPs and propose four benchmark regions that simultaneously accommodate a light long-lived particle and the CDF-II measured $\textit{W}$ boson mass. For these benchmarks, we present the reaches of FASER and FASER 2, where FASER 2 improves the sensitivity by approximately two orders of magnitude compared to FASER.

Xueying Qi

South Korea

Huayang Song

Wei Su

Complete light long-lived particles searches in Type-I 2HDM

The factorization proposal claims that the codimension one “pinning defect,” on which a local relevant operator is integrated, factorizes the space into two halves in general conformal field theories in the infrared limit. In this paper, we study a two-dimensional long-range Ising model at criticality with a line defect or an interface, which physically corresponds to changing the local temperature on it. We show that in the perturbative regime, it is not factorizing even in the infrared limit. An intuitive explanation of the nonfactorization is that the long-range Ising model is equivalent to a local conformal field theory in higher dimensions. In this picture, the space is still connected through the “extra dimension” across the defect line.

Japan

Dongsheng Ge

Yu Nakayama

Nonfactorizing interface in the two-dimensional long-range Ising model

The scale of the seesaw mechanism is typically much larger than the electroweak scale. This hierarchy can be naturally explained by U(1) symmetry, which after spontaneous symmetry breaking, simultaneously generates Majorana masses for neutrinos and produces a network of cosmic strings. Such strings generate a gravitational wave (GW) spectrum which is expected to be almost uniform in frequency unless there is a departure from the usual early radiation domination. We explore this possibility in Type I, II and III seesaw frameworks, finding that only for Type-I, long-lived right-handed neutrinos (RHN) may provide a period of early matter domination for parts of the parameter space, even if they are thermally produced. Such a period leaves distinctive imprints in the GW spectrum in the form of characteristic breaks and a knee feature, arising due to the end and start of the periods of RHN domination. These features, if detected, directly determine the right-handed neutrino mass $\textit{M}$, and associated left-handed effective neutrino mass $$ \overset{\sim }{m} $$ of the dominating RHN. We find that GW detectors like LISA and ET could probe RHN masses in the range $\textit{M}$ ∈ [0.1, 10 ] GeV and effective neutrino masses in the $$ \overset{\sim }{m} $$ ∈ [10 , 10 ] eV range. We investigate the phenomenological implications of long-lived right-handed neutrinos for both local and global U(1) strings, focusing on dark matter production and leptogenesis. We map the viable and detectable parameter space for successful baryogenesis and asymmetric dark matter production from right-handed neutrino decays. We derive analytical and semi-analytical relations correlating the characteristic gravitational-wave frequencies to the neutrino parameters $$ \overset{\sim }{m} $$ and $\textit{M}$, as well as to the relic abundances of dark matter and baryons. We find that the detectable parameter space reaches the boundary of hierarchical leptogenesis and encompasses a substantial portion of the near-resonant regime.

Satyabrata Datta

Poland

United Kingdom

Anish Ghoshal

Angus Spalding

Graham White

Gravitational wave spectral shapes as a probe of long lived right-handed neutrinos, leptogenesis and dark matter. Global versus local $\textit{B}$ − $\textit{L}$ cosmic strings

Dark sectors with confining gauge interactions can provide both simple dark matter candidates and striking signals at colliders. We recast Large Hadron Collider searches for two different signatures of dark mesons that arise from a strongly-coupled theory with vector-like dark quarks that are in some non-trivial representation of Standard Model SU(2) . For any such electroweak representation, there is a 3-plet of dark mesons whose charged components are long-lived, and we reinterpret searches for disappearing tracks to place a lower bound on their mass of ~ 1.2 TeV. When the dark quarks are in SU(2) representations larger than the fundamental, there is also a 5-plet of dark mesons that interacts with the electroweak gauge bosons via a chiral anomaly. We show that the 5-plet is the unique non-trivial meson multiplet with this anomaly and recast searches for the resulting diboson resonances to place bounds on model parameters. With additional measurements, the anomaly also enables one to reconstruct some ultraviolet parameters (the numbers of dark flavors and colors) while only measuring states in the infrared. Each of these signals represents an exciting opportunity for future searches using higher luminosity.

United States

Pouya Asadi

Austin Batz

Elias Bernreuther

Canada

Marco Costa

Samuel Homiller

Graham Kribs

Stopping dark mesons in their tracks with long-lived particle and resonant signatures

Heavy neutral leptons (HNLs) and axion-like particles (ALPs) are both considered well-motivated candidates for beyond the standard model (BSM) physics. If ALPs with sizable couplings to gluons exist, they will be abundantly produced at the LHC. Therefore, HNLs produced via the ALP portal may provide unprecedented sensitivities to HNL parameters. Here, we study the prospects for the high-luminosity LHC to search for long-lived HNLs. We consider future far detectors as well as ATLAS in our simulations. In the limit where the ALP mass is above the TeV scale, HNLs are effectively produced by a dimension-8 operator connecting HNL pairs to gluons. For completeness, we therefore also calculate future LHC sensitivities for HNLs produced via $\textit{N}$ SMEFT operators with gluons.

Spain

Cyprus

Rebeca Beltrán

Chandan Hati

Martin Hirsch

Ana Martín-Galán

Long-lived HNLs via ALP portal at the LHC

The long-distance contribution of QED corrections to the hadronic vacuum polarization is particularly challenging to compute in lattice <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>QCD</mi><mo>+</mo><mi>QED</mi></mrow></math>. Currently, it is one of the limiting factors toward matching the precision of the recent result by the Fermilab E989 experiment for the muon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>g</mi><mo>−</mo><mn>2</mn></mrow></math>. In this work, we present a method for obtaining high-precision results for this contribution by reconstructing exclusive finite-volume state contributions. We find relations between the pion-photon contributions of individual diagrams and demonstrate the reconstruction method with lattice <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>QCD</mi><mo>+</mo><mi>QED</mi></mrow></math> data at a single lattice spacing of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>a</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>≈</mo><mn>1.73</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><mo>≈</mo><mn>275</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>.

Germany

C. Lehner

J. Parrino

A. Völklein

Long-distance reconstruction of QED corrections to the hadronic vacuum polarization for the muon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math>

In this work, we study the long-range interactions in nongravitational field theories and their behavior in the deep infrared. To model such effects, we consider a nonlocal scalar theory obtained by adding a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><msup><mo>□</mo><mrow><mo>−</mo><mn>1</mn></mrow></msup><mi>ϕ</mi></math> term to the local action. Using the functional renormalization group, we analyze its infrared fixed-point structure. Within the local potential approximation (LPA), we show that nonlocality modifies phase-transition patterns and can induce symmetry breaking. Extending the LPA beyond polynomial truncations, we examine the convexity property of the effective potential as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi><mo stretchy="false">→</mo><mn>0</mn></math> and find that the flow becomes singular for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>λ</mi><mn>2</mn></msup><mo>&gt;</mo><mn>0</mn></math> before reaching the deep infrared. Including the scale-dependent wave function renormalization, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>k</mi></msub></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>LPA</mi><mo>′</mo></msup></math>), we find that the infrared-stable fixed point is the nonlocal Gaussian fixed point. We then generalize the model to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><msup><mo>□</mo><mrow><mi>σ</mi><mo>/</mo><mn>2</mn></mrow></msup><mi>ϕ</mi></math> and analyze how the infrared properties depend on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi></math>. With appropriate scaling choices, we show that the infrared behavior remains unchanged up to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi><mo>=</mo><mi>d</mi><mo>/</mo><mn>2</mn></math> and follows Sak’s prediction up to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi><mo>=</mo><mn>2</mn></math>. Finally, we study higher-derivative cases within the LPA, focusing on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi><mo>=</mo><mn>4</mn></math>, which corresponds to isotropic Lifshitz criticality, and obtain results consistent with earlier work.

Italy

Alfio M. Bonanno

India

S.R. Haridev

Gaurav Narain

RG studies of scalar-field models of long-range interactions

STRings for Absorption Length in Water (STRAW)-a and b were pathfinder instruments deployed to characterize the anticipated site of the Pacific Ocean Neutrino Experiment (P-ONE), which is a future neutrino telescope that will be located in the North Pacific Ocean. Measurements of the evolution of the optical transmission efficiency from STRAW-a showed a decline over the detector’s lifetime for the upward-facing modules. Video footage of the pathfinders strongly suggested this decline was caused by biofouling and sedimentation. We measure the effect of biofouling and sedimentation to be a decrease in the transparency of upward-facing optical surfaces over 5 years of operations. A majority of downward-facing optical surfaces, which will dominate P-ONE’s sensitivity to astrophysical sources, showed no visible biofouling. Extrapolations motivated by biological growth models estimated that these losses started around 2.5 years after deployment, and suggest a reduction in transparency ranging from 35 $$\%$$ of the original to complete obscuration for the upward-facing modules. Samples of biofouling were taken in order to identify the microbial diversity of these organisms and inform potential intervention strategies. Results of the microbial samples and a candidate anti-biofouling strategy that will be tested on upcoming P-ONE instruments are discussed.

O. Aghaei

M. Agostini

S. Agreda

A. Alexander Wight

P. Barbeau

A. Baron

S. Bash

C. Bellenghi

B. Biffard

M. Boehmer

M. Brandenburg

D. Brussow

N. Cedarblade-Jones

M. Charlton

B. Crudele

M. Danninger

F. C. De Leo

T. DeYoung

F. Fuchs

A. Gärtner

J. Garriz

D. Ghuman

L. Ginzkey

V. Gousy-Leblanc

D. Grant

A. Grimes

C. Haack

R. Halliday

D. Hembroff

F. Henningsen

J. Hutchinson

R. Jenkyns

S. Karanth

T. Kerscher

S. Kershtein

K. Kopański

C. Kopper

P. Krause

C. Krauss

I. Kulin

N. Kurahashi

C. Lagunas Gualda

A. Lam

T. Lavallee

K. Leismüller

R. Li

S. Loipolder

A. Magaña Ponce

S. Magel

P. Malecki

G. Marshall

T. Martin

S. Mihaly

C. Miller

N. Molberg

R. Moore

B. Nührenbörger

B. Nichol

W. Noga

R. Ørsøe

L. Papp

V. Parrish

M. Paulson

P. Pfahler

B. Pirenne

E. Price

A. Rahlin

M. Rangen

E. Resconi

C. Ridsdale

S. Robertson

A. Round

D. Salazar-Gallegos

A. Scholz

L. Schumacher

S. Sharma

C. Spannfellner

J. Stacho

I. Taboada

A. Thurber

M. Tradewell

J. Twagirayezu

M. Un Nisa

B. Veenstra

S. Wagner

C. Weaver

N. Whitehorn

L. Winter

M. Wolf

R. Wroński

J. Wynne

J. Yañez

A. Zaalishvili

Long term study of sedimentation and biofouling at cascadia basin, the site of the pacific ocean neutrino experiment

In the search for beyond the Standard Model (SM) physics, long-lived particles (LLPs) have emerged as potential candidates and are being explored in various ongoing experiments. Future lepton colliders, such as the FCC-ee, shall provide an excellent opportunity to probe LLPs, owing to their clean environment and improved particle identification. This study investigates the potential of the proposed Innovative Detector for an Electron-Positron Accelerator (IDEA) detector at FCC-ee in the detection of LLPs produced from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math>-meson and Higgs boson decays. We explore benchmark scenarios for different final states resulting from LLP decays, including a detailed analysis of the SM long-lived hadronic background. Additionally, we propose dedicated LLP detectors with different configurations, dimensions, and locations with respect to the IDEA detector. DELIGHT B, originally proposed as a dedicated LLP detector for the FCC-hh, stands out as the detector with the maximum efficiency for detecting LLPs produced at FCC-ee. We find that cylindrical detector configurations, if feasible to construct around the IDEA detector, would also enhance sensitivity for LLPs mostly decaying outside it.