We explore phenomenological constraints on, and future muon collider sensitivities to, the parameter spaces of various muonphilic portals to fermionic asymmetric dark matter (ADM). Both WEFT-level dimension-6 effective operators and two UV models based on gauged $\textit{L}$ – $\textit{L}$ are considered. One of the latter features a vector coupling to the dark matter and the other an axial vector coupling. The ADM criterion that at least 99% of the dark matter relic density is asymmetric is also imposed. We identify which of these scenarios are currently allowed by direct detection and collider constraints, and then determine how much more of the parameter space could be probed by 3 and 10 TeV muon colliders with 1 ab of data. For the UV models, the constraints from $\textit{g}$ – 2 of the muon are included. The future sensitivity curves due to neutron star heating considerations are also depicted. We present results for both the few-GeV dark matter mass regime motivated by ADM approaches to the Ω ≃ Ω /5 coincidence problem, and for larger masses in the context of more general ADM.

Australia

Arnab Roy

Raymond Volkas

Muonphilic asymmetric dark matter at a future muon collider

We consider constraints that can be placed on certain invisible scalar particles through monojet studies at the LHC and compare them with those from direct detection experiments when interpreted as dark matter. Whereas direct detection constraints are typically more restrictive, we identify regions of parameter space where monojet studies provide important complementary bounds. We carry out our analysis using both a $\textit{ϕ}$SMEFT for real scalar particle pairs coupled to standard-model fields through operators of up to dimension six, and a simple UV completion with vector-like quarks, with both the scalars and the vector-like quarks being odd under a $\textit{ℤ}$ symmetry, while the SM particles are even. The vector-like quarks can only decay into a jet and an invisible scalar, and we recast the current ATLAS monojet data to constrain their parameter space. Comparison of the two descriptions yields some insight into interpreting dark matter constraints obtained with EFTs.

Michael Schmidt

German Valencia

Monojet and direct detection constraints on real scalar dark matter: EFT and a simple UV completion

<p>A comprehensive analysis of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>K</mi><mo stretchy="false">→</mo><mi>π</mi><mi>K</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>π</mi><mo stretchy="false">→</mo><mi>K</mi><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover></math> amplitudes at large unphysical pion mass for all important partial waves is presented. A set of crossing-symmetric partial-wave hyperbolic dispersion relations is used to describe lattice quantum chromodynamics (QCD) data at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><mo>=</mo><mn>391</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>. In the present analysis, the amplitudes for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>- and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math>-waves are formulated by combining the constraints of analyticity, unitarity, and crossing symmetry, fulfilling Roy-Steiner-type equations. We use these results to investigate the low-lying strange-meson resonances and resolve the instability problem tied to analytic continuation in prior lattice QCD studies based on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi></math>-matrix formalism. At <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><mo>=</mo><mn>391</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>, the rigorous Roy-Steiner-type equation approach allows us to determine the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-wave scattering lengths, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><msubsup><mi>a</mi><mn>0</mn><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msubsup><mo>=</mo><mrow><mo stretchy="false">(</mo><mn>0.9</mn><msubsup><mn>2</mn><mrow><mo>−</mo><mn>0.28</mn></mrow><mrow><mo>+</mo><mn>0.06</mn></mrow></msubsup><mo stretchy="false">)</mo></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><msubsup><mi>a</mi><mn>0</mn><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msubsup><mo>=</mo><mo>−</mo><mrow><mo stretchy="false">(</mo><mn>0.3</mn><msubsup><mn>2</mn><mrow><mo>−</mo><mn>0.02</mn></mrow><mrow><mo>+</mo><mn>0.05</mn></mrow></msubsup><mo stretchy="false">)</mo></mrow></math>, and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>κ</mi></math> [also known as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>K</mi><mn>0</mn><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>700</mn><mo stretchy="false">)</mo></math>] pole position, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><msub><mi>s</mi><mi>κ</mi></msub></msqrt><mo>=</mo><mrow><mo stretchy="false">(</mo><mn>96</mn><msubsup><mn>6</mn><mrow><mo>−</mo><mn>24</mn></mrow><mrow><mo>+</mo><mn>41</mn></mrow></msubsup><mo>−</mo><mi>i</mi><mn>19</mn><msubsup><mn>8</mn><mrow><mo>−</mo><mn>17</mn></mrow><mrow><mo>+</mo><mn>38</mn></mrow></msubsup><mo stretchy="false">)</mo></mrow><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>. We also provide a detailed analysis of the complex validity domain of the Roy-Steiner-type equations.</p>

China

Xiong-Hui Cao

Feng-Kun Guo

Zhi-Hui Guo

Qu-Zhi Li

Revisiting Roy-Steiner-equation analysis of pion-kaon scattering from lattice QCD data

<p>We perform a rigorous analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>K</mi></math> scattering at an unphysical pion mass 391 MeV using the Roy-Steiner equations, which satisfy unitarity, analyticity, and crossing symmetry, for the first time. Stable solutions of the Roy-Steiner equations with different quantum numbers of isospin and angular momentum are obtained in the elastic energy region, by taking inputs from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>K</mi></math> lattice data in the inelastic region, the lattice data from the crossed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>π</mi><mo stretchy="false">→</mo><mi>K</mi><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover></math> channels, the masses of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>500</mn><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>*</mo></msup></math> at the same pion mass from previous study, and the Regge model. Predictions on the elastic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>K</mi></math> scattering phase shifts and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>K</mi><mn>0</mn><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>700</mn><mo stretchy="false">)</mo></math> pole content are made. Contrary to the virtual pole scenario obtained using the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi></math>-matrix method in the literature, we find that lightest strange scalar meson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>K</mi></mrow><mrow><mn>0</mn></mrow><mrow><mo>*</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>700</mn><mo stretchy="false">)</mo></mrow></math> remains a broad resonance at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><mo>=</mo><mn>391</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>. The cross-channel dynamics is found to play a crucial role in deriving the proper pole position.</p>

Rigorous Roy-Steiner equation analysis of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>K</mi></math> scattering at unphysical quark masses

We consider the constraints on new physics affecting rare kaon and hyperon decay as parametrized by a low energy effective theory that can be obtained from high-p observables at LHC. To this end, we match the relevant low energy Wilson coefficients onto those in SMEFT at dimension six and compute their contributions to charged dilepton, monolepton, monojets, and VH searches by ATLAS and CMS. Constraints from rare kaon decays are generally more restrictive, with the ones arising from high-p measurements complementing them along directions in parameter space to which the former are not sensitive. We also illustrate the effect of a high luminosity LHC run in reducing the viable parameter regions.

High-p

Motivated by the LHCb measurement of the hyperon decay mode <math><mrow><msup><mrow><mi>Σ</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>→</mo><mi>p</mi><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> and prospects for improvement, we revisit the estimates for the rate and muon forward-backward asymmetry within the standard model and beyond. The standard model prediction has a fourfold ambiguity, and we suggest ways to resolve it with other measurements, including possible studies of <math><msup><mi>Σ</mi><mo>+</mo></msup><mo>→</mo><mi>p</mi><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> in the BESIII and LHCb experiments. We use the recent BESIII measurements of <math><msup><mi>Σ</mi><mo>+</mo></msup><mo>→</mo><mi>p</mi><mi>γ</mi></math> and <math><msup><mi>Σ</mi><mo>+</mo></msup><mo>→</mo><mi>N</mi><mi>π</mi></math> to reduce the uncertainty in the long-distance contribution to <math><msup><mi>Σ</mi><mo>+</mo></msup><mo>→</mo><mi>p</mi><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math>. Beyond the standard model, we consider a general effective Hamiltonian at low energy with ten operators whose Wilson coefficients parametrize the new physics. We derive expressions for the <math><msup><mi>Σ</mi><mo>+</mo></msup><mo>→</mo><mi>p</mi><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> rate and the associated muon forward-backward asymmetry in terms of these coefficients. Finally, we present the constraints on these Wilson coefficients that result from both kaon and hyperon decays and emphasize their complementarity.

Jusak Tandean

<math><msup><mi>Σ</mi><mo>+</mo></msup><mo>→</mo><mi>p</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> decays within the standard model and beyond

We reappraise the viability of asymmetric dark matter (ADM) realized as a Dirac fermion coupling dominantly to the Standard Model fermions. Treating the interactions of such a DM particle with quarks/leptons in an effective-interactions framework, we derive updated constraints using mono-jet searches from the Large Hadron Collider (LHC) and mono-photon searches at the Large Electron-Positron (LEP) collider. We carefully model the detectors used in these experiments, which is found to have significant impact. The constraint of efficient annihilation of the symmetric part of the ADM, as well as other observational constraints are synthesized to produce a global picture. Consistent with previous work, we find that ADM with mass in the range 1–100 GeV is strongly constrained, thus ruling out its best motivated mass range. However, we find that leptophilic ADM remains allowed for ≳ 10 GeV DM, including bounds from colliders, direct detection, and stellar heating. We forecast that the Future Circular Collider for electron-positron collisions (FCC-ee) will improve sensitivity to DM-lepton interactions by almost an order of magnitude.

India

Basudeb Dasgupta

Monoranjan Guchait

Constraining Asymmetric Dark Matter using colliders and direct detection

A reliable determination of the pole parameters and residues of nucleon resonances is notoriously challenging, given the required analytic continuation into the complex plane. We provide a comprehensive analysis of such resonance parameters accessible with Roy–Steiner equations for pion–nucleon scattering—a set of partial-wave dispersion relations that combines the constraints from analyticity, unitarity, and crossing symmetry—most prominently of the <math><mi>Δ</mi><mo>(</mo><mn>1232</mn><mo>)</mo></math> resonance. Further, we study the Roper, <math><mi>N</mi><mo>(</mo><mn>1440</mn><mo>)</mo></math>, resonance, which lies beyond the strict domain of validity, in comparison to Padé approximants, comment on the role of subthreshold singularities in the S-wave, and determine the residues of the <math><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mn>500</mn><mo>)</mo></math>, <math><mi>ρ</mi><mo>(</mo><mn>770</mn><mo>)</mo></math>, and <math><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mn>980</mn><mo>)</mo></math> resonances in the t-channel process <math><mi>π</mi><mi>π</mi><mo>→</mo><mover><mrow><mi>N</mi></mrow><mrow><mo>¯</mo></mrow></mover><mi>N</mi></math>. The latter allows us to test—for the first time fully model independently in terms of the respective residues—universality of the <math><mi>ρ</mi><mo>(</mo><mn>770</mn><mo>)</mo></math> couplings and the Goldberger–Treiman relation expected if the scalars behaved as dilatons, in both cases revealing large deviations from the narrow-resonance limit.

Switzerland

Martin Hoferichter

Spain

Jacobo Ruiz de Elvira

Germany

Bastian Kubis

Ulf-G. Meißner

Nucleon resonance parameters from Roy–Steiner equations

We explore a possible signal of the presence of relatively light electroweakinos (ewinos) and a singlet-like scalar (a  S ) of the Z 3-symmetric Next-to-Minimal Supersymmetric Standard Model (Z 3-NMSSM) in the cascade decays of not so heavy top squarks (  <math> <msub> <mi>m</mi> <msub> <mover> <mi>t</mi> <mo>~</mo> </mover> <mn>1</mn> </msub> </msub> </math>  $$ {m}_{{\tilde{t}}_1} $$  ≲ 1.5 TeV) that may be produced in pairs at the Large Hadron Collider LHC. We work in a scenario where the lightest (next-to-lightest) SUSY particle is bino (singlino)-like with its mass below 100 GeV and is mildly tempered with higgsino and singlino admixtures. The singlet-like scalar provides an annihilation funnel for the bino-like states such that the latter could act as a viable dark matter candidate, unlike what is now highly constrained in the MSSM. We consider a pair of immediately heavier neutralinos and the lighter chargino which all are higgsino-like with masses in the range ~ 0.5–1 TeV and are still compatible with all experimental constraints. While these states may not be accessible in their direct searches at the LHC in our present scenario, such ewinos could still be traced in the decays of the top squarks of the above-mentioned kind. We consider the signal final state    at the LHC. We find that while a usual cut-based analysis (CBA) of LHC data worth 300 fb −1 would be unable to discover such excitations, a multivariate analysis (MVA) can be reasonably sensitive to higgsino-like ewinos having masses ≳ 650 GeV when   <math> <msub> <mi>m</mi> <msub> <mover> <mi>t</mi> <mo>~</mo> </mover> <mn>1</mn> </msub> </msub> </math>  $$ {m}_{{\tilde{t}}_1} $$  ≳ 1 TeV. On the other hand, with 3000 fb −1 of data, these masses become accessible in a CBA while even an MVA on such a data set is unlikely to find these ewinos with masses around 1 TeV when   <math> <msub> <mi>m</mi> <msub> <mover> <mi>t</mi> <mo>~</mo> </mover> <mn>1</mn> </msub> </msub> </math>  $$ {m}_{{\tilde{t}}_1} $$  hits ∼ 1.5 TeV.

AseshKrishna Datta

Subhojit Roy

Hunting ewinos and a light scalar of Z 3-NMSSM with a bino-like dark matter in top squark decays at the LHC

We study the top-quark production along with a Higgs boson and a jet (tHq) at the LHC experiment within the framework of the Standard Model Effective Field Theory (SMEFT). A strategy is developed to constrain the Wilson Coefficients (WC) corresponding to the associated SMEFT operators using the latest LHC measurements. The best-fit values of these WCs are presented. Finally, we demonstrate the feasibility of finding the effects of these operators on various kinematical observables of the tHq process at the LHC. We find that for a set of best-fitted values of the considered WCs, the excess of signal over the backgrounds can be achieved with a reasonable significance at the center of mass energy $$ \sqrt{s} $$ = 13 TeV and for integrated luminosity options $$ \mathcal{L} $$ =300 fb and 3000 fb .