We derive two rigorous bounds on the spectrum of massive states that contributes to planar amplitudes in weakly coupled theories with massless scalars. First, we show that the presence of massive spinning states necessitates the existence of lighter states with lower spins. Explicitly, if there exists a massive state with spin $\textit{J}$ > 2, then there must be a state with spin $\textit{J}$ − 1 and a non-zero mass lower than that of the lightest spin-$\textit{J}$ state, a state with spin $\textit{J}$ − 2 and a mass lower than that of the lightest spin-($\textit{J}$ − 1) particle and so on until we reach a mass below which only states with spin less than 2 are exchanged. Second, we find that if there are spin-$\textit{J}$ states in the spectrum, the maximum mass of the lightest spin-($\textit{J}$ + 1) state is determined by the masses of the lightest spin-$\textit{J}$ and ($\textit{J}$ − 1) states. In the approximation that this bound applies to pion scattering in real world QCD, we find it gives a window of only ∼150 MeV for the expected mass of a yet unmeasured spin-7 meson.

United States

Justin Berman

Analytic bounds on the spectrum of crossing symmetric S-matrices

The first search for a heavy neutral spin-1 gauge boson (<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>) with nonuniversal fermion couplings produced via vector boson fusion processes and decaying to tau leptons or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> bosons is presented. The analysis is performed using LHC data 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>, collected from 2016 to 2018 with the CMS experiment and corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>138</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The data are consistent with the standard model predictions. Upper limits are set on the product of the cross section for production of the <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> boson and its branching fraction to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mi>τ</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>W</mi></math>. The presence of a <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> boson decaying to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math>) is excluded for masses up to 2.45(1.60) TeV, depending on the <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> boson coupling to standard model weak bosons, and assuming a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>Z</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow><mo stretchy="false">→</mo><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math>) branching fraction of 50%.

Armenia

A. Hayrapetyan

A. Tumasyan

Austria

W. Adam

J.W. Andrejkovic

L. Benato

T. Bergauer

S. Chatterjee

K. Damanakis

M. Dragicevic

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

T. Van Laer

P. Van Mechelen

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

S. Lowette

I. Makarenko

D. Müller

S. Tavernier

M. Tytgat

G.P. Van Onsem

S. Van Putte

D. Vannerom

B. Bilin

B. Clerbaux

A.K. Das

I. De Bruyn

G. De Lentdecker

H. Evard

L. Favart

P. Gianneios

J. Jaramillo

A. Khalilzadeh

F.A. Khan

K. Lee

A. Malara

S. Paredes

M.A. Shahzad

L. Thomas

M. Vanden Bemden

C. Vander Velde

P. Vanlaer

M. De Coen

D. Dobur

G. Gokbulut

Y. Hong

J. Knolle

L. Lambrecht

D. Marckx

K. Mota Amarilo

K. Skovpen

N. Van Den Bossche

J. van der Linden

L. Wezenbeek

A. Benecke

A. Bethani

G. Bruno

C. Caputo

J. De Favereau De Jeneret

C. Delaere

I.S. Donertas

A. Giammanco

A.O. Guzel

Sa. Jain

V. Lemaitre

J. Lidrych

P. Mastrapasqua

T.T. Tran

Brazil

G.A. Alves

E. Coelho

G. Correia Silva

C. Hensel

T. Menezes De Oliveira

C. Mora Herrera

P. Rebello Teles

M. Soeiro

A. Vilela Pereira

W.L. Aldá Júnior

M. Barroso Ferreira Filho

H. Brandao Malbouisson

W. Carvalho

J. Chinellato

E.M. Da Costa

G.G. Da Silveira

D. De Jesus Damiao

Search for a Neutral Gauge Boson with Nonuniversal Fermion Couplings in Vector Boson Fusion Processes in Proton-Proton Collisions 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>

Motivated by a recent Belle II measurement that suggests an excess in the rare decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>K</mi><msub><mi>E</mi><mrow><mi>miss</mi></mrow></msub></math>, and building upon our recent differential decay rate likelihood analysis of the existing experimental information, we investigate possible new physics (NP) scenarios in which light invisible states participate in flavor-changing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi></math> transitions. In particular, we consider the total and differential <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msup><mi>K</mi><mo>*</mo></msup><msub><mi>E</mi><mrow><mi>miss</mi></mrow></msub></math> decay rates and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>*</mo></msup></math> polarization effects in each NP scenario preferred by the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>K</mi><msub><mi>E</mi><mrow><mi>miss</mi></mrow></msub></math> measurement. We show that future measurements of these <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msup><mi>K</mi><mo>*</mo></msup><msub><mi>E</mi><mrow><mi>miss</mi></mrow></msub></math> observables will offer decisive discrimination among the different NP explanations. Our results highlight the strong complementarity of the rare semi-invisible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi></math>-hadron decay observables, and underline the importance of analysing their momentum transfer spectra when probing extensions of the Standard Model that feature new light degrees of freedom.

Slovenia

Patrick D. Bolton

Svjetlana Fajfer

Jernej F. Kamenik

Spain

Martín Novoa-Brunet

Impact of new invisible particles on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup><msub><mi>E</mi><mrow><mi>miss</mi></mrow></msub></math> observables

We clarify and extend our earlier work [1, 2] where it was shown how to amend a scheme originally proposed by M. Gell-Mann to identify the three families of quarks and leptons of the Standard Model with the 48 spin- $$ \frac{1}{2} $$ fermions of $\textit{N}$ = 8 supergravity that remain after absorption of eight Goldstinos, a scheme that in its original form is dynamically realized at the SU(3) × U(1) stationary point of gauged $\textit{N}$ = 8 supergravity. We explain how to deform and enlarge this symmetry at the kinematical level to the full Standard Model symmetry group SU(3) $\textit{×}$SU(2) $\textit{×}$U(1) , with the correct charge and chiral assignments for all fermions. The framework also leaves room for an extra U(1) symmetry. This symmetry enhancement is achieved by embedding the Standard Model symmetries into (a quotient group of) K(E ), the ‘maximal compact subgroup’ of the maximal rank hyperbolic Kac-Moody symmetry E , and an infinite prolongation of the SU(8) $\textit{R}$-symmetry of $\textit{N}$ = 8 supergravity. This scheme, which is also supposed to encompass quantum gravity, cannot be realized within the framework of space-time based (quantum) field theory, but requires space-time and related geometrical concepts to be ‘emergent’. We critically review the main hypotheses underlying this construction.

Poland

Krzysztof Meissner

Germany

Hermann Nicolai

Standard model symmetries and K(E

In this paper we study the notion of complexity under time evolution in chaotic quantum systems with holographic duals. Continuing on from our previous work, we turn our attention to the issue of Krylov complexity upon the insertion of a class of single-particle operators in the double-scaled SYK model. Such an operator is described by a matter-chord insertion, which splits the theory into left/right sectors, allowing us, via chord-diagram technology, to compute two different notions of complexity associated to the operator insertion: first a Krylov operator complexity, and second the Krylov complexity of a state obtained by an operator acting on the thermofield double state. We will provide both an analytic proof and detailed numerical evidence, that both Krylov complexities arise from a recursively defined basis of states characterized by a constant total chord number. As a consequence, in all cases we are able to establish that Krylov complexity is given by the expectation value of a length operator acting on the Hilbert space of the theory, expressed in terms of basis states, organized by left and right chord number. We find analytic expressions for the semiclassical limit of K-complexity, and study how the size of the operator encodes the scrambling dynamics upon the matter insertion in Krylov language. We furthermore determine the effective Hamiltonian governing the evolution of K-complexity, showing that evolution on the Krylov chain can equivalently be understood as a particle moving in a Morse potential. A particular type of triple scaling limit allows to access the gravitational sector of the theory, in which the geometrical nature of K-complexity is assured by virtue of being a total chord length, in an analogous fashion to what was found in [1] for the K-complexity of the thermofield double state.

Switzerland

M. Ambrosini

Israel

E. Rabinovici

United Kingdom

A. Sánchez-Garrido

Luxembourg

R. Shir

J. Sonner

Operator K-complexity in DSSYK: Krylov complexity equals bulk length

The isospin-selective reaction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi>L</mi></msub><mi>p</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi mathvariant="normal">Σ</mi><mn>0</mn></msup></math> provides a clean probe for investigating <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>I</mi><mo>=</mo><mn>1</mn><mtext> </mtext><mtext> </mtext><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup></math> resonances. In this work, we perform an analysis of this reaction using an effective Lagrangian approach for the first time, incorporating the well-established <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1189</mn><mo stretchy="false">)</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1385</mn><mo stretchy="false">)</mo><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1670</mn><mo stretchy="false">)</mo><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1775</mn><mo stretchy="false">)</mo><mn>5</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></math> states, while also exploring contributions from other unestablished states. By fitting the available differential cross-section and recoil polarization data, adhering to partial-wave phase conventions same as the Particle Data Group, we find that besides the established resonances, contributions from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1660</mn><mo stretchy="false">)</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1580</mn><mo stretchy="false">)</mo><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></math>, and a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup><mo stretchy="false">)</mo></math> improve the description. Notably, a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup><mo stretchy="false">)</mo></math> resonance with mass around 1.54 GeV, consistent with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1620</mn><mo stretchy="false">)</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></math>, is found to be essential for describing the data in this channel, a stronger indication than found in previous analyses focusing on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi mathvariant="normal">Λ</mi></math> final states. While providing complementary support for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1660</mn><mo stretchy="false">)</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1580</mn><mo stretchy="false">)</mo><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></math>, our results highlight the importance of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1620</mn><mo stretchy="false">)</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></math> region in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi>L</mi></msub><mi>p</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi mathvariant="normal">Σ</mi><mn>0</mn></msup></math>. Future high-precision measurements are needed to solidify these findings and further constrain the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup></math> spectrum.

China

Dan Guo

Jun Shi

Igor Strakovsky

Bing-Song Zou

Analysis of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup></math> via isospin selective reaction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi>L</mi></msub><mi>p</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi mathvariant="normal">Σ</mi><mn>0</mn></msup></math>

This study investigates the consistency of heterotic supergravity, where the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math>-field gauge transformation becomes anomalous due to the Green-Schwarz mechanism, under <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-duality transformations. We establish that preserving <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math> duality necessitates an infinite tower of higher-derivative couplings proportional to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mrow><mo>−</mo><mn>2</mn><mi mathvariant="normal">Φ</mi></mrow></msup></math>. For spacetimes featuring a Killing self-dual circle, these couplings remain immune to quantum corrections. Leveraging <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> duality in heterotic or type I string theory, we then identify the corresponding couplings in type I theory. Notably, our analysis reveals that standard <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-duality transformations do not involve higher-derivative corrections. Building on this insight, we derive the explicit form of the effective action for type I theory at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>α</mi><mo>′</mo></msup></math> order, adhering to a scheme that omits derivatives of the dilaton.

Iran

Mohammad R. Garousi

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> duality in higher-derivative corrections of heterotic supergravity

As was shown in <inter-ref xmlns:ns0='http://www.w3.org/1999/xlink' ns0:role='http://www.elsevier.com/xml/linking-roles/preprint' ns0:href='arxiv:1203.1054' id='inf0010'>arXiv:1203.1054</inter-ref>, expanding the Nambu action near the &#8220;long string&#8221; vacuum in the static gauge one finds that the one-loop <math altimg='si1.svg'><mn>2</mn><mo stretchy='false'>&#8594;</mo><mn>2</mn></math> scattering amplitude of the <math altimg='si2.svg'><mi>D</mi><mo linebreak='goodbreak' linebreakstyle='after'>&#8722;</mo><mn>2</mn><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>24</mn></math> transverse 2d fluctuations <math altimg='si3.svg'><msup><mrow><mi>X</mi></mrow><mrow><mi>i</mi></mrow></msup></math> is given by a pure phase expression consistent with underlying integrability. Similar computation in the Green-Schwarz superstring was carried out in <inter-ref xmlns:ns0='http://www.w3.org/1999/xlink' ns0:role='http://www.elsevier.com/xml/linking-roles/preprint' ns0:href='arxiv:2404.09658' id='inf0020'>arXiv:2404.09658</inter-ref>. Here we consider the case of the NSR or spinning string starting with its manifestly 2d covariant action given by <italic>D</italic> scalar multiplets coupled to 2d supergravity. Integrating out the zweibein and gravitino fields is not straightforward so that a Nambu-like version of the spinning string action involving only the scalar coordinates and their 2d fermionic partners was not given in the past. We show how the elimination of the auxiliary fields can be done in the static gauge after a particular choice of the superconformal gauges on the fermions while keeping the transverse fields <math altimg='si3.svg'><msup><mrow><mi>X</mi></mrow><mrow><mi>i</mi></mrow></msup></math> and <math altimg='si4.svg'><msup><mrow><mi>&#968;</mi></mrow><mrow><mi>i</mi></mrow></msup></math> off-shell. The resulting one-loop S-matrix for <math altimg='si3.svg'><msup><mrow><mi>X</mi></mrow><mrow><mi>i</mi></mrow></msup></math> turns out, as expected, to be the same as in the GS superstring case. We also discuss similar actions for the heterotic string and a <math altimg='si125.svg'><mi>T</mi><mover accent='true'><mrow><mi>T</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></math> deformation of a free 2d scalar multiplet.

Arkady A. Tseytlin

Zihan Wang

On world-sheet S-matrix of NSR string in static gauge

The momentum-differential invariant cross sections of $\textit{π}$ and $\textit{η}$ mesons are reported for pp collisions at $$\sqrt{s}$$ = 13 TeV at midrapidity ($\textit{|y| <}$ 0$\textit{.}$8). The measurement is performed in a broad transverse-momentum range of 0$\textit{.}$2 $\textit{< p}$ $\textit{<}$ 200 GeV/$\textit{c}$ and 0$\textit{.}$4 $\textit{< p}$ $\textit{<}$ 60 GeV/$\textit{c}$ for the $\textit{π}$ and $\textit{η}$, respectively, extending the $\textit{p}$ coverage of previous measurements. Transverse-mass-scaling violation of up to 60% at low transverse momentum has been observed, agreeing with measurements at lower collision energies. Transverse Bjorken $\textit{x}$ ($\textit{x}$ ) scaling of the $\textit{π}$ cross sections at LHC energies is fulfilled with a power-law exponent of $\textit{n}$ = 5$\textit{.}$01 ± 0$\textit{.}$05, consistent with values obtained for charged pions at similar collision energies. The data are compared to predictions from next-to-leading order perturbative QCD calculations, where the $\textit{π}$ spectrum is best described using the CT18 parton distribution function and the NNFF1.0 or BDSS fragmentation function. Expectations from PYTHIA8 and EPOS LHC overestimate the spectrum for the $\textit{π}$ and are not able to describe the shape and magnitude of the $\textit{η}$ spectrum. The charged-particle multiplicity dependent $\textit{π}$ and $\textit{η p}$ spectra show the expected change of the spectral shape, characterized by a flatter slope with increasing multiplicity. This is demonstrated across a broad transverse-momentum range and up to events with a charged-particle multiplicity exceeding five times the mean value in minimum bias collisions. The $\textit{η/π}$ ratio depends on the charged-particle multiplicity for $\textit{p}$ $\textit{<}$ 4 GeV/$\textit{c}$. PYTHIA8 and EPOS LHC qualitatively explain this behavior with an increasing contribution from the feed-down of heavier particles to the $\textit{π}$ spectrum.

France

S. Acharya

India

A. Agarwal

G. Aglieri Rinella

Italy

L. Aglietta

M. Agnello

N. Agrawal

Z. Ahammed

S. Ahmad

South Korea

S. Ahn

Slovakia

I. Ahuja

A. Akindinov

V. Akishina

M. Al-Turany

D. Aleksandrov

B. Alessandro

H. Alfanda

Mexico

R. Alfaro Molina

B. Ali

A. Alici

N. Alizadehvandchali

A. Alkin

Norway

J. Alme

G. Alocco

T. Alt

A. Altamura

I. Altsybeev

J. Alvarado

M. Anaam

Romania

C. Andrei

N. Andreou

A. Andronic

E. Andronov

V. Anguelov

F. Antinori

P. Antonioli

N. Apadula

L. Aphecetche

H. Appelshäuser

C. Arata

S. Arcelli

R. Arnaldi

J. Arneiro

Light neutral-meson production in pp collisions at $$\sqrt{\text{s}}$$ = 13 TeV