A measurement of the branching fraction for the decay $$ \Lambda \to p{\mu}^{-}{\overline{\nu}}_{\mu } $$ is presented using $\textit{pp}$ collision data collected by the LHCb experiment at a centre-of-mass energy of 13 TeV. The analysis is based on data recorded between 2016 and 2018, corresponding to an integrated luminosity of 5.4 fb . The result is obtained using Λ $\textit{→ pμ}$ decays as a normalisation channel. The measured branching fraction is $$ \mathcal{B}\left(\Lambda \to p{\mu}^{-}{\overline{\nu}}_{\mu}\right)=\left(1.462\pm 0.016\pm 0.100\pm 0.011\right)\times {10}^{-4} $$ , where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalisation mode branching fraction, respectively. This result improves the precision of the branching fraction measurement by a factor of two compared to the previous best measurement and sets a more stringent bound on lepton flavour universality in $\textit{s → u}$ quark transitions. It is consistent with previous measurements, and the extracted lepton flavour universality test observable, $$ {R}^{\mu e}=\frac{\Gamma \left(\Lambda \to p{\mu}^{-}{\overline{\nu}}_{\mu}\right)}{\Gamma \left(\Lambda \to p{e}^{-}{\overline{\nu}}_e\right)}=0.175\pm 0.012 $$ , agrees with the Standard Model prediction.

Netherlands

R. Aaij

United Kingdom

A. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A. Adefisoye

Spain

B. Adeva

M. Adinolfi

Sweden

P. Adlarson

France

C. Agapopoulou

C. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Italy

P. Albicocco

Germany

J. Albrecht

Lithuania

R. Aleksiejunas

F. Alessio

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J. Amey

Y. Amhis

China

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. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J. Back

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. Barbosa

R. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

Poland

S. Bashir

B. Batsukh

P. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I. Bediaga

N. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

C. Betancourt

F. Betti

J. Bex

Ia. Bezshyiko

Ukraine

O. Bezshyyko

J. Bhom

M. Bieker

N. Biesuz

P. Billoir

A. Biolchini

M. Birch

F. Bishop

A. Bitadze

A. Bizzeti

Branching fraction measurement of the $$ \Lambda \to p{\mu}^{-}{\overline{\nu}}_{\mu } $$ decay

The first four-dimensional amplitude analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mo>+</mo></msup></math> decay is performed with proton-proton collision data collected by the LHCb experiment at <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"><mrow><mn>5.4</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">f</mi><msup><mrow><mi mathvariant="normal">b</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math>. The data cannot be fully explained by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>K</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup></math> contributions alone. A significantly better description of the data is obtained by adding a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></mrow><mo>+</mo></msubsup></math> contribution decaying to <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><msup><mi>π</mi><mo>+</mo></msup></math>. The properties of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></mrow><mo>+</mo></msubsup></math> structure are consistent with the exotic state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> reported in the isospin-related <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>K</mi><mo>−</mo></msup><msup><mi>π</mi><mo>+</mo></msup></math> decay. Effects of a possible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup><mo stretchy="false">→</mo><msubsup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mn>1</mn><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>2600</mn><msup><mo stretchy="false">)</mo><mn>0</mn></msup><msup><mi>D</mi><mo>+</mo></msup></math> decay mode on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>π</mi><mo>+</mo></msup></math> mass distribution are investigated through a Flatté parametrization, providing constraints on the relative decay strength. A description of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> structure using the triangle singularity mechanism is studied and also found to be consistent with the data.

A.S.W. Abdelmotteleb

A.A. Adefisoye

C.A. Aidala

M. Akthar

J.L. Amey

J.A. Authier

J.J. Back

I.R. Barbosa

R.J. Barlow

P.B. Battista

I.B. Bediaga

N.A. Behling

M.S. Bieker

N.V. Biesuz

F.C.R. Bishop

T. Blake

F. Blanc

Observation and investigation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> structure in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mo>+</mo></msup></math> decays

In all previous calculations of the nonlocal subleading contribution to the inclusive penguin decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi>X</mi><mi>s</mi></msub><mi>γ</mi></math> due to the interference of the electroweak operators <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="script">O</mi><mn>1</mn><mi>c</mi></msubsup><mo>−</mo><msub><mi mathvariant="script">O</mi><mrow><mn>7</mn><mi>γ</mi></mrow></msub></math> the local Voloshin term was subtracted. In view of the ongoing analysis at order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mi>s</mi></msub></math>, we present a calculation of the complete nonlocal contribution which takes into account the high correlation between the uncertainties of the local Voloshin and the nonlocal term of the previous analyses. The new calculation has a high impact on the range of the nonlocal contribution.

Michael Benzke

Maria Vittoria Garzelli

Tobias Hurth

Addendum to “Resolved <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><msub><mi>m</mi><mi>b</mi></msub></math> contributions to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi>X</mi><mrow><mi>s</mi><mo>,</mo><mi>d</mi></mrow></msub><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi>X</mi><mi>s</mi></msub><mi>γ</mi></math>”

A search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>K</mi><mrow><mi mathvariant="normal">S</mi><mo stretchy="false">(</mo><mi mathvariant="normal">L</mi><mo stretchy="false">)</mo></mrow><mn>0</mn></msubsup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> decays is performed 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"><mn>5.4</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. No <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>K</mi><mrow><mi mathvariant="normal">S</mi><mo stretchy="false">(</mo><mi mathvariant="normal">L</mi><mo stretchy="false">)</mo></mrow><mn>0</mn></msubsup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> signals are found and upper limits are set for the first time on the branching fractions <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><mrow><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">)</mo></mrow></mrow><mo>&lt;</mo><mn>1.4</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">L</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><mrow><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">)</mo></mrow></mrow><mo>&lt;</mo><mn>6.6</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>7</mn></mrow></msup></mrow></math>, at the 90% confidence level.

S. Bhattacharya

Search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>K</mi></mrow><mrow><mrow><mi mathvariant="normal">S</mi><mo stretchy="false">(</mo><mi mathvariant="normal">L</mi><mo stretchy="false">)</mo></mrow></mrow><mn>0</mn></msubsup><mo stretchy="false">→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><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 at LHCb

Charged-hadron distributions in heavy-flavor jets are measured in proton-proton collisions at a center-of-mass energy of $$ \sqrt{s}=13 $$ TeV collected by the LHCb experiment. Distributions of the longitudinal momentum fraction, transverse momentum, and radial profile of charged hadrons are measured separately in beauty and charm jets. The distributions are compared to those previously measured by the LHCb collaboration in jets produced back-to-back with a $\textit{Z}$ boson, which in the forward region are primarily light-quark-initiated, to compare the hadronization mechanisms of heavy and light quarks. The observed differences between the heavy- and light-jet distributions are consistent with the heavy-quark dynamics expected to arise from the dead-cone effect, as well as with a hard fragmentation of the heavy-flavor hadron as previously measured in single-hadron fragmentation functions. This measurement provides additional constraints for the extraction of collinear and transverse-momentum-dependent heavy-flavor fragmentation functions and offers another approach to probing the mechanisms that govern heavy-flavor hadronization.

Measurement of charged-hadron distributions in heavy-flavor jets in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV

This study presents a novel interpretation of complexity in the formalism of <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> gravity, where <italic>R</italic> specifies the Ricci scalar, <math altimg='si2.svg'><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub></math> is written as matter Lagrangian that describes characteristics of the matter fields, and <math altimg='si3.svg'><mi mathvariant='script'>T</mi></math> represents the trace of energy-momentum tensor. We commence with the contemplation of the inner sector as a cylindrical configuration having anisotropic matter and linked with the exterior region through a hypersurface. We determine the modified field equations associated with <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> gravity and assume the preliminarily established relations between the conformal tensor and the intrinsic curvature. We consider the generally employed mathematical expressions for Tolman mass and C-Energy and evaluate their relationship with the conformal tensor. The structural scalars are calculated from orthogonal splitting of Riemann tensor, out of which <italic>Y<inf>TF</inf></italic> is categorized as complexity factor for the inferred fluid composition. It is important to specify that the complexity factor is eradicated in the framework of uniform matter configuration and also in the scenario when anisotropic terms are canceled with each other. Significant results related to the Weyl scalar, Tolman mass, and the complexity factor are derived in <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> gravity. The vanishing complexity constraint is considered in order to deal with the modified field equations that have extra degrees of freedom and to find particular solutions corresponding to the specific models.

Pakistan

A. Rehman

Azerbaijan

M. Yousaf

Uzbekistan

Bekzod Rahmatov

Javlon Rayimbaev

Munisbek Akhmedov

Complexity evaluation related to the cylindrically symmetric anisotropic matter in <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> theory

Accurate measurements of fundamental cosmological parameters, especially the Hubble constant ( $$H_0$$ ) and present-day matter density ( $$\Omega _\mathrm{{m} 0}$$ ), are crucial for constraining dark energy (DE) evolution. We analyze the sensitivities of cosmological observables ($\textit{H}$($\textit{z}$), $$D_L(z)$$ , $$\text {E}_{\text {G}}$$ ) to $$\Omega _\mathrm{{m} 0}$$ , $$\omega _{0}$$ , and $$\omega _{a}$$ under different parametrizations. Our results show observables are far more sensitive to $$\Omega _\mathrm{{m} 0}$$ than to DE equation of state parameters (e.g., at $$z \sim 0.5$$ , $\textit{H}$($\textit{z}$)’s $$\Omega _\mathrm{{m} 0}$$ sensitivity is $$\sim 0.7$$ vs. $$\omega _{a}$$ ’s $$\sim 0.04$$ ). This hierarchy mandates high-precision $$\Omega _\mathrm{{m} 0}$$ measurements to accurately constrain time-varying DE. We also find DE parameter sensitivity highly depends on parametrization; the standard CPL form shows low sensitivity to $$\omega _{a}$$ , but $$\omega (z) = \omega _{0}+ \omega _{a}\ln (1+z)$$ significantly enhances it. Our analysis of DESI DR1/DR2 data confirms these theoretical limits: standalone DESI data primarily provides only upper limits for $$\omega _{a}$$ , underscoring insufficient constraining power for a definitive time-varying DE detection. While combined datasets offer tighter constraints, interpretation requires caution due to parametrization influence. We further confirm this point using simulated Supernovae MCMC data. In conclusion, improving $$\Omega _\mathrm{{m} 0}$$ precision and adopting optimized parametrizations are imperative for future surveys like DESI to fully probe dark energy’s nature.

South Korea

Seokcheon Lee

Probing time-varying dark energy with DESI: the crucial role of precision matter density ( $$\Omega _\mathrm{{m} 0}$$ ) measurements

We propose and evaluate a source-equals-detector search for the deexcitation of the long-lived isomer <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> in natural tantalum (Ta), using a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray transition-edge-sensor (TES) array. Two capabilities absent in conventional high-purity germanium (HPGe) searches are exploited: (i) near-unity containment of low-energy secondaries [internal-conversion (IC) electrons and characteristic x-rays] and of the nuclear recoil, enabling a calorimetric, event-by-event measurement of the total deposited energy in the absorber; and (ii) a delayed-coincidence tag using the subsequent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn></mrow></mmultiscripts></mrow></math> electron-capture (EC) decay to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Hf</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn></mrow></mmultiscripts></mrow></math>. We evaluate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mi>σ</mi></math> discovery reach for IC and for dark-matter (DM)-induced deexcitation in two benchmark scenarios: a strongly interacting DM subcomponent and inelastic DM with off diagonal couplings. Using a background model based on intrinsic radioactivity in the Ta absorber and realistic detector performance, we show that arrays with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>N</mi></mrow><mrow><mi>TES</mi></mrow></msub><mo>=</mo><mn>256</mn></mrow></math> and 1,000 pixels can reach the theoretically expected IC half-life within 2.6 yr and 0.66 yr, respectively. For an array with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>TES</mi></msub><mo>=</mo><msup><mn>10</mn><mn>4</mn></msup></math> and a five-year exposure, the projected sensitivity to DM-induced de-excitation surpasses limits inferred from HPGe nonobservations of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> and probes regions of parameter space not covered by current direct-detection experiments.

A. Gando

K. Ichimura

K. Ishidoshiro

T. Kikuchi

T. Kishimoto

A. Takeuchi

R. Sato

R. Smith

Probing internal conversion and dark-matter-induced deexcitation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> with a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray TES array

A search for long-lived heavy neutral leptons produced in B-meson decays and decaying to a μ π final state is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5 fb . The results are interpreted in both lepton-number-conserving and lepton-number-violating scenarios. No significant excess is observed. Constraints are placed on the squared mixing element |$\textit{U}$ | to the active muon neutrino, under the assumption that couplings to other lepton flavours are negligible, in the mass range of 1$\textit{.}$6–5$\textit{.}$5 GeV.

Hungary

Search for heavy neutral leptons in B-meson decays

The $\textit{pp}$ → $\textit{W}$ (→ $\textit{μ}$ $\textit{ν}$ )$\textit{X}$ cross-sections are measured at a proton-proton centre-of-mass energy $$ \sqrt{s}=5.02 $$ TeV using a dataset corresponding to an integrated luminosity of 100 pb recorded by the LHCb experiment. Considering muons in the pseudorapidity range 2$\textit{.}$2 $\textit{< η <}$ 4$\textit{.}$4, the cross-sections are measured differentially in twelve intervals of muon transverse momentum between 28 $\textit{< p}$ $\textit{<}$ 52 GeV. Integrated over $\textit{p}$ , the measured cross-sections are

Measurement of the $\textit{W → μν}$ cross-sections as a function of the muon transverse momentum in $\textit{pp}$ collisions at 5.02 TeV