We study the Higgs boson decays $$h \rightarrow Z\gamma $$ and $$h \rightarrow m_VZ$$ in a model with vectorlike fermions and $$U(1)_X$$ symmetry ( $$U(1)_X$$ VLFM), where $$m_V$$ is a vector meson ( $$\rho ,\ \omega ,\ \phi ,\ J/\psi ,\ \Upsilon $$ ). The exotic Yukawa interactions in this model generate mixing between Standard Model (SM) fermions and vectorlike fermions, and this mixing affects the Higgs boson mass and Higgs couplings. The corrections to the CP-even and CP-odd $$h\gamma Z$$ couplings come from loop diagrams that involve the new particles, and these corrections have a clear impact on the decay rates of $$h\rightarrow Z\gamma $$ and $$h\rightarrow m_VZ$$ . In suitable regions of the parameter space, the model can produce non-negligible deviations in $$\Gamma _\textrm{NP}(h\rightarrow Z\gamma )/\Gamma _\textrm{SM}(h\rightarrow Z\gamma )$$ and $$\Gamma _\textrm{NP}(h\rightarrow m_VZ)/\Gamma _\textrm{SM}(h\rightarrow m_V Z)$$ , providing possible signals of new physics (NP) beyond the SM.

China

Rong-Zhi Sun

Shu-Min Zhao

Yue-Tong Liu

Portugal

Xing-Xing Dong

Higgs boson decays $$h\rightarrow Z \gamma $$ and $$h\rightarrow m_V Z$$ in the $$U(1)_X$$ VLFM

A flavor-tagged time-dependent analysis of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> decays is performed across the full dimuon mass range excluding the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> resonance regions. The analysis uses proton-proton collision data collected by the LHCb experiment in 2011–2018 at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>9</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation parameters are determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>C</mi><mo>=</mo><mo>−</mo><mn>0.13</mn><mo>±</mo><mn>0.32</mn><mo>±</mo><mn>0.04</mn></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>S</mi><mo>=</mo><mo>+</mo><mn>0.82</mn><mo>±</mo><mn>0.29</mn><mo>±</mo><mn>0.05</mn></mrow></math>, where the first uncertainties are statistical and the second are systematic. The results are consistent with the standard model prediction. This is the first experimental study of time-dependent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> processes.

Netherlands

R. Aaij

United Kingdom

A.S.W. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A.A. Adefisoye

Spain

B. Adeva

M. Adinolfi

P. Adlarson

France

C. Agapopoulou

C.A. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Italy

P. Albicocco

Germany

J. Albrecht

R. Aleksiejunas

CERN

F. Alessio

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J.L. Amey

Y. Amhis

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

C. Arata

F. Archilli

Z. Areg

M. Argenton

Costa Rica

S. Arguedas Cuendis

L. Arnone

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

J.A. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J.J. Back

Z.B. Bai

P. Baladron Rodriguez

V. Balagura

A. Balboni

W. Baldini

Z. Baldwin

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I.R. Barbosa

R.J. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

Poland

S. Bashir

B. Batsukh

P.B. Battista

A. Bavarchee

A. Bay

A. Beck

M. Becker

F. Bedeschi

I.B. Bediaga

N.A. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

A. Bertolin

F. Betti

J. Bex

O. Bezshyyko

S. Bhattacharya

M.S. Bieker

N.V. Biesuz

A. Biolchini

M. Birch

F.C.R. Bishop

A. Bitadze

A. Bizzeti

T. Blake

F. Blanc

First Measurement of Time-Dependent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> Violation in the Flavor-Changing Neutral-Current Decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math>

The collinear and transverse-momentum-dependent jet fragmentation function and the radial profile for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup></math> mesons in jets are measured. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup></math> mesons are reconstructed through the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><mo stretchy="false">(</mo><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup><mo stretchy="false">)</mo><msup><mi>K</mi><mo>±</mo></msup></math> decay channel using proton-proton collision data collected during 2016–2018 with the LHCb detector at a center-of-mass (c.m.) energy of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5.4</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The results complement recent measurements of jet fragmentation functions for heavy-flavor hadrons and suggest a growing contribution of gluon fragmentation to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup></math> mesons as the jet transverse momentum increases.

M. Arias

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math>-jet fragmentation with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>K</mi><mo>±</mo></msup></math> decays in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions at LHCb

In this work, we perform a comprehensive phenomenological analysis of the exotic hadronic states <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>4020</mn><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>10610</mn><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>10650</mn><mo stretchy="false">)</mo></math> within the framework of heavy quark spin symmetry (HQSS) and its violation. By constructing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-wave contact interactions between elastic (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup><mo>/</mo><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><msup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup><mo>/</mo><msup><mi>B</mi><mo>*</mo></msup><msup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math>) and inelastic (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>π</mi><mo>,</mo><msub><mi>h</mi><mi>c</mi></msub><mi>π</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mi>π</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>b</mi></msub><mi>π</mi></math>) channels, we solve the Lippmann-Schwinger equation to obtain physical production amplitudes and perform a global fit to experimental invariant-mass spectra. Our results demonstrate a striking difference between the charm and bottom sectors: HQSS violation is negligible in the bottom system, leading to comparable peak structures for both <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>b</mi></msub></math> states in all hidden-bottom decay channels. In contrast, significant HQSS breaking is required to describe the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub></math> system, where the violation is predominantly concentrated in the elastic interactions. This explains the observed selectivity: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> appears prominently only in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>π</mi></math>, while <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>4020</mn><mo stretchy="false">)</mo></math> appears only in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>c</mi></msub><mi>π</mi></math>. Regardless of whether HQSS violation is taken into account, both the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>10610</mn><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>10650</mn><mo stretchy="false">)</mo></math> poles can appear near the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><msup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>*</mo></msup><msup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> thresholds, respectively. In the hidden charm sector, however, only the framework that includes HQSS violation can successfully describe the experimental data, leading to a single pole around the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> threshold, which is identified as the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math>. Meanwhile, the structure associated with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>4020</mn><mo stretchy="false">)</mo></math> is interpreted as a cusp effect. The robustness of our model is verified against variations of the form factor and cutoff, showing stable results.

Quanxing Ye

Ying Zhang

Peng-Yu Niu

Japan

Qian Wang

Why is the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> absent in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>c</mi></msub><mi>π</mi></math> final state?

We consider the hypothetical possibility of neutral gauge bosons (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math>) with flavor-specific leptophilic couplings. For such New Physics (NP) interactions, the current experimental constraints are much more relaxed in the heavy mass regime, particularly for masses <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≥</mo><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mn>1</mn><mo stretchy="false">)</mo><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>. However, in the presence of a leptophilic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math>, leptonic decay modes of the electroweak gauge bosons and Higgs can be corrected at the loop level. Using the existing upper bounds on the corresponding decay widths, we find that one can impose stronger exclusion limits on the interactions of a heavy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math>. Future updates on the aforesaid decay channels can be used in complementarity with the proposed lepton colliders to probe even weaker leptophilic NP interactions at the TeV scale and beyond.

India

Bibhabasu De

Amitabha Dey

Constraining the heavy leptophilic neutral gauge bosons through the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>Z</mi><mo stretchy="false">→</mo><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>−</mo></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>±</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mo>ℓ</mo></mrow></msub></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mo stretchy="false">→</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> decays

In many new physics models with extended gauge symmetry, the new gauge boson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> could mediate the interactions between the dark matter and standard model particles. For the conventional <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> portal dark matter, the collider and the direct detection constraints typically pose a significant challenge. To address this pressing issue, we present in this paper a new benchmark model based on the gauged <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><mi>B</mi><mo>−</mo><mi>L</mi></mrow></msub></math> symmetry, which introduces a Dirac dark fermion <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>χ</mi><mo stretchy="false">˜</mo></mover><mn>1</mn></msub></math> and a heavier partner <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>χ</mi><mo stretchy="false">˜</mo></mover><mn>2</mn></msub></math> with zero and nonzero <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><mi>B</mi><mo>−</mo><mi>L</mi></mrow></msub></math> charge, respectively. Including the mass term <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>δ</mi><mi>m</mi><msub><mover accent="true"><mover accent="true"><mi>χ</mi><mo stretchy="false">˜</mo></mover><mo stretchy="false">¯</mo></mover><mn>1</mn></msub><msub><mover accent="true"><mi>χ</mi><mo stretchy="false">˜</mo></mover><mn>2</mn></msub></math> results in the dark fermions <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>1</mn></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>2</mn></msub></math> in the mass eigenstate, where the lighter one <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>1</mn></msub></math> is regarded as the dark matter candidate. Various intriguing processes for the relic density arise with the compressed mass spectrum <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><msub><mi>χ</mi><mn>1</mn></msub></msub><mo>≃</mo><msub><mi>m</mi><msub><mi>χ</mi><mn>2</mn></msub></msub></math>, such as the coscattering <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>2</mn></msub><mi>f</mi><mo stretchy="false">→</mo><msub><mi>χ</mi><mn>1</mn></msub><mi>f</mi></math>, the conversion <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>2</mn></msub><msub><mi>χ</mi><mi>i</mi></msub><mo stretchy="false">→</mo><msub><mi>χ</mi><mn>1</mn></msub><msub><mi>χ</mi><mi>j</mi></msub></math>, and the coannihilation <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>1</mn></msub><msub><mi>χ</mi><mn>2</mn></msub><mo stretchy="false">→</mo><mi>f</mi><mover accent="true"><mi>f</mi><mo stretchy="false">¯</mo></mover></math> processes. Suppressed by the small mixing angle <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>θ</mi></math> between the dark fermions, the small effective gauge coupling of dark matter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>1</mn></msub></math> to the gauge boson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> is one distinct feature of this model, rendering phenomenology in many aspects more promising. In this paper, we investigate the production of dark matter through new mechanisms within the frameworks of resonance and secluded scenarios. The impacts of phenomenological constraints from colliders, dark matter, and cosmology are also taken into account. We report that the conversion mechanism is both favored by the resonance and secluded scenarios under current constraints.

Zhen-Wei Wang

Zhi-Long Han

Fei Huang

Honglei Li

Ang Liu

Reviving <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>Z</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math> portal dark matter with conversion mechanism

The first measurements of the top- and antitop-quark differential production cross sections and the top-quark charge asymmetry in the forward region are presented, using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>5.4</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The total production cross sections of top and antitop quarks are also determined. Measurements are performed using the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi><mo>+</mo><mrow><mi>b</mi><mtext>-jet</mtext></mrow></mrow></math> final state within a fiducial region defined by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>b</mi></mrow></math>-jet <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi><mo>,</mo><mtext>jet</mtext></mrow></msub><mo>&gt;</mo><mn>50</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> and pseudorapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2.2</mn><mo>&lt;</mo><msub><mrow><mi>η</mi></mrow><mrow><mtext>jet</mtext></mrow></msub><mo>&lt;</mo><mn>4.0</mn></mrow></math>, with the muon from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-boson decay required to have <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi><mo>,</mo><mi>μ</mi></mrow></msub><mo>&gt;</mo><mn>25</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.0</mn><mo>&lt;</mo><msub><mi>η</mi><mi>μ</mi></msub><mo>&lt;</mo><mn>4.5</mn></math>. The muon and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>b</mi></mrow></math>-jet system must satisfy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi></mrow></msub><mo stretchy="false">(</mo><mi>μ</mi><mo>+</mo><mtext>jet</mtext><mo stretchy="false">)</mo><mo>&gt;</mo><mn>20</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>. The measured integrated production cross sections for the top and antitop quarks are <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>=</mo><mn>0.95</mn><mo>±</mo><mn>0.04</mn><mo>±</mo><mn>0.08</mn><mo>±</mo><mn>0.02</mn><mtext> </mtext><mtext> </mtext><mi>pb</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mover accent="true"><mrow><mi>t</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></msub><mo>=</mo><mn>0.81</mn><mo>±</mo><mn>0.03</mn><mo>±</mo><mn>0.07</mn><mo>±</mo><mn>0.02</mn><mtext> </mtext><mtext> </mtext><mi>pb</mi></mrow></math>, where the first uncertainty is statistical, the second systematic, and the third accounts for the luminosity uncertainty. The top-quark charge asymmetry is measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>A</mi></mrow><mrow><mi>C</mi></mrow><mrow><mi>t</mi></mrow></msubsup><mo>=</mo><mn>0.08</mn><mo>±</mo><mn>0.03</mn><mo>±</mo><mn>0.01</mn></mrow></math>, where the first uncertainty is statistical and the second is systematic. These results are consistent with next-to-leading order Standard Model predictions.

M. Akthar

S. Bernet Andres

Measurement of the Top-Quark Production Cross Section and Charge Asymmetry at LHCb

This study examines the $ h\to Z\gamma $ and $ h\to\gamma\gamma $ decays in the flavor-gauged two Higgs doublet model (FG2HDM), which augments the Standard Model (SM) with an additional scalar doublet, a singlet, and a $ U(1)' $ flavor gauge symmetry. Beyond the SM spectrum, FG2HDM predicts five additional physical scalars and a new neutral gauge boson, $ Z' $ . We demonstrate that while both decay channels are sensitive to charged Higgs loops, $ h \to Z\gamma $ is uniquely modified by fermion-antifermion-$\textit{Z}$ ( $ f\bar{f}Z $ ) vertex corrections. These vertex corrections further impact top-quark observables and the flavor-changing neutral current (FCNC) process $ b\to s\ell^+\ell^- $ . Our analysis identifies a viable parameter space ( $ m_{H^\pm} \gt 200 $ GeV and $ \lambda_{hH^+H^-} \lt 0 $ ) consistent with current $ 1\sigma $ experimental limits, where the signal strength $ \mu_{\gamma\gamma} $ remains the primary constraint on scalar sector parameters. Regarding the $ f\bar{f}Z $ couplings, we delineate the allowed regions in the $ \mathcal{Q}_{tL} $ - $ \mathcal{Q}_{tR} $ plane by evaluating the leading top-quark contributions, revealing that $ b\to s\ell^+\ell^- $ imposes the most stringent bounds. Finally, we highlight that the $ 14\% $ projected precision for $ \mu_{Z\gamma} $ at the High-Luminosity LHC (HL-LHC) will significantly enhance sensitivity to the FG2HDM.

Feng-Zhi Chen

Qiaoyi Wen

Fanrong Xu

Higgs decays to $\textit{Z}$ $\textit{γ}$ and $\textit{γ}$ $\textit{γ}$ in the flavor-gauged two Higgs doublet model * Supported by NSFC (12475095, U1932104), the Fundamental Research Funds for the Central Universities (11623330) and the 2024 Guangzhou Basic and Applied Basic Research Scheme Project for Maiden Voyage (2024A04J4190)

The Galactic Center GeV Excess (GCE) remains a compelling but enigmatic signal from the inner regions of our galaxy. Muonphilic dark matter (DM), which couples exclusively to muons via a new mediator, provides a viable explanation for the GCE and relic density while naturally evading constraints from direct detection, collider searches, and other multimessenger observations. Based on the viable nonresonant parameter space identified in previous global fits, we perform a comprehensive study on the prospects for discovering such muonphilic DM in the context of a future 3 TeV muon collider, focusing on simplified models with a $Z_2$ -even mediator. Four distinct search strategies are investigated: visible on-shell mediator decays ( $\mu^{+}\mu^{-}\gamma$ final state), invisible on-shell mediator decays (mono-photon plus missing energy), mono-photon production via off-shell mediators, and vector boson fusion production. Through a detailed signal-background analysis using cut-and-count methods, we project the exclusion limits at $ 95 $ % confidence level for seven representative models across a wide range of mediator masses. Our results demonstrate that the projected limits cover a significant portion of viable parameter space that explains the GCE, establishing a muon collider as a decisive machine for testing the muonphilic DM hypothesis.

Wanyun Chen

Haoqi Li

Chih-Ting Lu

Qiulei Wang

Exploring muonphilic dark matter with the $\textit{Z}$ $_{2}$-even mediator at muon colliders * Chih-Ting Lu, Wanyun Chen and Haoqi Li are supported by the National Natural Science Foundation of China (NNSFC) (12335005, 12575118) and the Special funds for postdoctoral overseas recruitment, Ministry of Education of China

Vector boson scattering (VBS) serves as a powerful channel for probing the Standard Model (SM), particularly the electroweak symmetry breaking mechanism. Currently, studies of VBS mainly focus on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo stretchy="false">→</mo><mn>2</mn></math> scattering. In this study, we investigate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo stretchy="false">→</mo><mn>3</mn></math> VBS process of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>pp</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>γ</mi><mi>γ</mi><mo>+</mo><mn>2</mn><mtext> </mtext><mtext> </mtext><mi>jets</mi></math> through Monte Carlo simulations, including signal generation and background analysis. The signal significance is evaluated across different phase-space regions. With an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>500</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, the signal significance can reach about <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.5</mn><mi>σ</mi></math>. Furthermore, the analysis is extended to a beyond the SM scenario involving Higgs boson decays into a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson and an axionlike particle, providing projected exclusion limits on the relevant coupling parameters. These results suggest that, given the ongoing release of the LHC Run 3 dataset, there will be promising opportunities to explore and potentially discover a series of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo stretchy="false">→</mo><mn>3</mn></math> VBS processes, starting with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi><mi>γ</mi><mi>γ</mi></math> channel.

Ran Ding

Ruobing Jiang

Tianyi Yang

Andrew Levin

Qiang Li

Prospects for measuring electroweak production of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi><mi>γ</mi><mi>γ</mi></math> and two jets at the LHC