Neutrino oscillation experiments have confirmed that neutrinos are massive particles and that lepton flavors are mixed. To explain the observed lepton mass spectra and flavor mixing patterns, flavor symmetry plays a crucial and unique role. In this paper, we propose a useful symmetry-breaking scheme by applying $S_{3L} \times S_{3R} \rightarrow $ $ S_{2L} \times S_{2R} \rightarrow \emptyset$ within both charged-lepton and neutrino sectors at the mass-matrix level. For the three distinct residual subgroups $S_{2L}^{(23)} \times S_{2R}^{(23)}$ , $S_{2L}^{(13)} \times S_{2R}^{(13)}$ , and $S_{2L}^{(12)} \times S_{2R}^{(12)}$ that are under consideration, we systematically analyze the various parameterizations of the lepton mass matrices. It is shown that all three scenarios are in good agreement with current neutrino oscillation data. Notably, within the latest best-fit values of neutrino oscillation parameters, the predicted values of the Dirac CP-violating phase $\textit{δ}$ are $294.6^\circ$ , $302.3^\circ$ , and $287.0^\circ$ , respectively. To further assess the viability of the model, a comprehensive numerical analysis is performed by utilizing neutrino oscillation parameters at the $3\sigma$ level. It is found that the allowed ranges of $\textit{δ}$ are $281.2^\circ \rightarrow 338.7^\circ$ , $287.0^\circ \rightarrow 342.2^\circ$ , and $282.7^\circ \rightarrow 297.0^\circ$ , which all fall within its $3\sigma$ range. These results indicate that the proposed symmetry-breaking scheme $S_{3L} \times S_{3R} \rightarrow S_{2L} \times S_{2R} \rightarrow \emptyset$ can naturally explain the realistic lepton mass hierarchy and mixing pattern, thereby providing valuable theoretical perspectives for future research.

China

Chang-Qi Hu

Chun-Yuan Li

Xiao Liang

Xing-Hua Yang

Dai-Xing Zhang

Further study on lepton mass spectra and flavor mixing with $\textit{S}$ 3$\textit{L}$ × $\textit{S}$ 3$\textit{R}$ flavor symmetry * Supported in part by the National Natural Science Foundation of China (12105162, 12305106), the Natural Science Foundation of Shandong Province (ZR2021QA058, ZR2021QA040) and the Youth Innovation Technology Project of Higher School in Shandong Province (2023KJ146)

We formulate a general fusion procedure for open $$\mathfrak{g}\mathfrak{l}(N)$$ spin chains. We construct the fused boundary reflection matrices and the corresponding fused reflection equations. By using the intertwining relation between the fused reflection matrices and the fusion operator, we identify the invariant subspace of the fused reflection matrices carrying the irreducible representations of $$\mathfrak{g}\mathfrak{l}(N)$$ . We also construct the fused transfer matrix and evaluate it explicitly in the total tensor product space and the invariant subspaces. Finally, we demonstrate that the ABJM spin chain model originates from such fusion procedure and derive three classes of boundary reflection matrices solutions on the anti-fundamental representation space of $$\mathfrak{s}\mathfrak{u}(4)$$ .

Nan Bai

A general fusion procedure for open $$\mathfrak{g}\mathfrak{l}(N)$$ spin chains: application to the ABJM spin chain

We study the collider phenomenology of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo>−</mo><mi>L</mi></math> extension of the Standard Model (BLSM), focusing on the production and decay of a heavy neutral gauge boson (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math>) at the Large Hadron Collider (LHC). In this framework, the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> can decay into pairs of heavy right-handed neutrinos (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>R</mi></msub></math>), which subsequently decay into charged leptons and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> bosons. These processes give rise to three distinctive final states: (i) two leptons plus four jets (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo>ℓ</mo><mo>+</mo><mn>4</mn><mi>j</mi></math>), (ii) four leptons plus missing transverse energy (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mo>ℓ</mo><mo>+</mo><mi>MET</mi></math>), and (iii) three leptons plus two jets and MET (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mo>ℓ</mo><mo>+</mo><mn>2</mn><mi>j</mi><mo>+</mo><mi>MET</mi></math>). To enhance signal sensitivity and suppress Standard Model backgrounds, we employ multivariate analysis techniques based on boosted decision trees (BDTs), as well as selection optimizations using the xgboost framework. The classifiers are trained on kinematic observables sensitive to the masses of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>R</mi></msub></math>. We demonstrate that all three final states offer significant discovery potential for both the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> and heavy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>R</mi></msub></math> at the High-Luminosity LHC. Our results highlight the testability of the BLSM at current and future collider experiments, and provide a promising avenue for probing the origin of neutrino masses and the baryon asymmetry of the Universe.

Egypt

Kareem Ezzat

Syria

Germany

Nidal Chamoun

Shaaban Khalil

Rhitaja Sengupta

Exploring <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> and right-handed neutrinos in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo>−</mo><mi>L</mi></math> symmetric SM at the Large Hadron Collider

A search for a dark baryon is performed for the first time in the two-body decay <math altimg='si14.svg'><mrow><msup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mo>&#8722;</mo></msup><mo>&#8594;</mo><msup><mi>&#960;</mi><mo>&#8722;</mo></msup><mo linebreak='goodbreak'>+</mo><mrow><mrow><mi mathvariant='normal'>i</mi></mrow><mi>n</mi><mi>v</mi><mi>i</mi><mi>s</mi><mi>i</mi><mi>b</mi><mi>l</mi><mi>e</mi></mrow></mrow></math> using (10.087&#8239;&#177;&#8239;0.044)&#8239;&#215;&#8239;10 9 <italic>J</italic>/ <italic>&#968;</italic> events collected at a center-of-mass energy of <math altimg='si23.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>3.097</mn><mspace width='0.16em' /><mtext>GeV</mtext></mrow></math> with the BESIII detector at the BEPCII collider. No significant signal is observed, and the 90% (95%) confidence level upper limits on the branching fraction <math altimg='si24.svg'><mrow><mi mathvariant='script'>B</mi><mo>(</mo><msup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mo>&#8722;</mo></msup><mo>&#8594;</mo><msup><mi>&#960;</mi><mo>&#8722;</mo></msup><mo linebreak='goodbreak'>+</mo><mrow><mrow><mi mathvariant='normal'>i</mi></mrow><mi>n</mi><mi>v</mi><mi>i</mi><mi>s</mi><mi>i</mi><mi>b</mi><mi>l</mi><mi>e</mi></mrow><mo>)</mo></mrow></math> are determined to be <math altimg='si25.svg'><mrow><mn>4.2</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></mrow></math> ( <math altimg='si26.svg'><mrow><mn>5.2</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></mrow></math>), <math altimg='si27.svg'><mrow><mn>6.9</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></mrow></math> ( <math altimg='si28.svg'><mrow><mn>8.4</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></mrow></math>), <math altimg='si29.svg'><mrow><mn>6.5</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>4</mn></mrow></msup></mrow></math> ( <math altimg='si30.svg'><mrow><mn>7.6</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>4</mn></mrow></msup></mrow></math>), <math altimg='si31.svg'><mrow><mn>1.1</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>4</mn></mrow></msup></mrow></math> ( <math altimg='si32.svg'><mrow><mn>1.3</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>4</mn></mrow></msup></mrow></math>) and <math altimg='si33.svg'><mrow><mn>4.5</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></mrow></math> ( <math altimg='si34.svg'><mrow><mn>5.5</mn><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></mrow></math>), under the dark baryon mass hypotheses of 1.07&#8201;GeV/ <italic>c</italic> 2, 1.10&#8201;GeV/ <italic>c</italic> 2, <math altimg='si19.svg'><msub><mi>m</mi><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle></msub></math> (1.116&#8201;GeV/ <italic>c</italic> 2), 1.13&#8201;GeV/ <italic>c</italic> 2, and 1.16&#8201;GeV/ <italic>c</italic> 2, respectively. The constraints obtained on the Wilson coefficients <math altimg='si17.svg'><msubsup><mi>C</mi><mrow><mi>u</mi><mi>s</mi><mo>,</mo><mi>s</mi></mrow><mi>L</mi></msubsup></math> and <math altimg='si18.svg'><msubsup><mi>C</mi><mrow><mi>u</mi><mi>s</mi><mo>,</mo><mi>s</mi></mrow><mi>R</mi></msubsup></math> are more stringent than the previous limits derived from the LHC searches for the colored mediators.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

O. Bakina

Y. Ban

H.-R Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. De Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Search for a dark baryon in the <math altimg='si14.svg'><mrow><msup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mo>&#8722;</mo></msup><mo>&#8594;</mo><msup><mi>&#960;</mi><mo>&#8722;</mo></msup><mo linebreak='goodbreak'>+</mo><mrow><mrow><mi mathvariant='normal'>i</mi></mrow><mi>n</mi><mi>v</mi><mi>i</mi><mi>s</mi><mi>i</mi><mi>b</mi><mi>l</mi><mi>e</mi></mrow></mrow></math> decay

The MicroBooNE experiment is an 85 tonne active mass liquid argon time projection chamber neutrino detector exposed to the on-axis Booster Neutrino Beam at Fermilab. One of MicroBooNE’s physics goals is the precise measurement of neutrino interactions on argon in the 1 GeV energy regime. Building on the capabilities of the MicroBooNE detector, this analysis identifies <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup></math> mesons, a key signature for the study of strange particle production in neutrino interactions. This measurement is furthermore valuable for background estimation for future nucleon decay searches and for improved reconstruction and particle identification capabilities in experiments such as the Deep Underground Neutrino Experiment. In this Letter, we present the first-ever measurement of a flux-integrated cross section for charged-current muon neutrino induced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup></math> production on argon nuclei, determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>7.93</mn><mo>±</mo><mn>3.22</mn><mo stretchy="false">(</mo><mi>stat</mi><mo stretchy="false">)</mo><mo>±</mo><mn>2.83</mn><mo stretchy="false">(</mo><mi>syst</mi><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>42</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>/</mo><mi>nucleon</mi></mrow></math> based on an analysis of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>6.88</mn><mo>×</mo><msup><mn>10</mn><mn>20</mn></msup></math> protons on target. This result was found to be consistent with model predictions from different neutrino event generators within the reported uncertainties.

P. Abratenko

D. Andrade Aldana

L. Arellano

J. Asaadi

Israel

A. Ashkenazi

S. Balasubramanian

B. Baller

A. Barnard

G. Barr

D. Barrow

J. Barrow

V. Basque

J. Bateman

O. Benevides Rodrigues

S. Berkman

A. Bhat

M. Bhattacharya

M. Bishai

A. Blake

B. Bogart

T. Bolton

M.B. Brunetti

L. Camilleri

D. Caratelli

F. Cavanna

G. Cerati

A. Chappell

Y. Chen

J.M. Conrad

M. Convery

L. Cooper-Troendle

Spain

J.I. Crespo-Anadón

R. Cross

M. Del Tutto

S.R. Dennis

P. Detje

Switzerland

R. Diurba

Z. Djurcic

K. Duffy

S. Dytman

B. Eberly

P. Englezos

A. Ereditato

J.J. Evans

C. Fang

G.A. Fiorentini Aguirre

W. Foreman

B.T. Fleming

D. Franco

A.P. Furmanski

F. Gao

D. Garcia-Gamez

S. Gardiner

G. Ge

S. Gollapinni

E. Gramellini

P. Green

H. Greenlee

L. Gu

W. Gu

R. Guenette

P. Guzowski

L. Hagaman

M.D. Handley

O. Hen

C. Hilgenberg

G.A. Horton-Smith

A. Hussain

B. Irwin

M.S. Ismail

First Measurement of Charged-Current Muon-Neutrino-Induced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup></math> Production on Argon Using the MicroBooNE Detector