In this paper, we study non-supersymmetric $\textit{AdS}$ × $\textit{S}$ vacuua of $\textit{O}$(16) × $\textit{O}$(16) heterotic theory on a string scale $\textit{T}$ background, which are parameterized by a pair of flux integers. Adding the one-loop scalar potential to the effective theory contributes positively to the cosmological constant, but we find that there is no uplift to de Sitter for any values of the fluxes. We study the fluctuations around these vacua and show that all scalar and tensor modes from the six-dimensional effective theory lie above the Breitenlohner-Freedman bound. The moduli coming from the torus compactification will also be above the bound, at least for a large range of fluxes.

United States

Daniel Robbins

Hassaan Saleem

$\textit{O}$(16) $\textit{× O}$(16) heterotic theory on $\textit{AdS}$ 3 $\textit{× S}$ 3 $\textit{× T}$ 4

The reduced cross section of the semiexclusive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>l</mi><mo>,</mo><msup><mi>l</mi><mo>′</mo></msup><mi>p</mi><mo stretchy="false">)</mo></math> lepton scattering process irrespective of the type of interaction is determined mainly by the bound nucleon momentum distribution in the target and nucleon final state interaction with the residual nucleus. These cross sections can be identified with distorted nuclear spectral functions and therefore, they are similar up to Coulomb corrections for neutrino and electron scattering on nuclei. In this article, we exploit this similarity and use data with precise kinematics and large statistics for semiexclusive electron scattering on an oxygen target to test models employed in the genie neutrino event generator. We find that these models cannot reproduce well the measured reduced cross sections in all allowed kinematic regions and the genie event generator needs to describe better both the nuclear ground states and nucleon final state interaction. The approach presented in this paper provides a great opportunity to better test the accuracy of nuclear models of quasielastic neutrino-nucleus scattering, employed in neutrino event generators.

Russia

A.V. Butkevich

S.V. Luchuk

Test of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathsize="small">G</mi><mi mathsize="small">E</mi><mi mathsize="small">N</mi><mi mathsize="small">I</mi><mi mathsize="small">E</mi></mrow></math> neutrino event generator against reduced cross sections extracted from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mmultiscripts><mrow><mi mathvariant="normal">O</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>16</mn></mrow></mmultiscripts></mrow><mo stretchy="false">(</mo><mi>e</mi><mo>,</mo><msup><mrow><mi>e</mi></mrow><mrow><mo>′</mo></mrow></msup><mi>p</mi><mo stretchy="false">)</mo></mrow></math> data

We continue to explore the previously suggested dual regime of Yang-Baxter (YB) deformed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></math> sigma models, which is a new one-parametric deformation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></math> model. It can be obtained from the conventional YB deformed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo>+</mo><mn>2</mn><mo stretchy="false">)</mo></math> sigma model by freezing two isometries. The scattering matrix in the nondeformed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mi>n</mi><mo stretchy="false">)</mo></math> model is known to coincide with the rational <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mrow><mi mathvariant="fraktur">so</mi></mrow><mi>n</mi></msub></math>-invariant <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi></math>-matrix. For <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>n</mi><mo>=</mo><mn>2</mn><mi>N</mi></math> this rational solution allows for two trigonometric deformations: the usual <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>N</mi><mrow><mo stretchy="false">(</mo><mn>1</mn><mo stretchy="false">)</mo></mrow></msubsup></math> and the twisted <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>N</mi><mrow><mo stretchy="false">(</mo><mn>2</mn><mo stretchy="false">)</mo></mrow></msubsup></math>. The usual one is known to coincide with the scattering matrix of the conventional YB-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></math> model. A natural question to ask is what sigma model corresponds to the twisted solution. In this work we claim that it is precisely our dual regime of YB-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></math>. We find the corresponding unitarizing function <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>F</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mi>θ</mi><mo stretchy="false">)</mo></math> explicitly, and, as a bonus, extract some physical properties of this system using the thermodynamic Bethe ansatz technique.

Alexey Bychkov

Boris Nekrasov

Scattering in the dual regime of Yang-Baxter deformed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">O</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></mrow></math> sigma models

First information on the timelike electromagnetic structure of baryons in the second resonance region has been obtained from measurements of the dielectron (e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math>) invariant mass and angular distributions with the High Acceptance Di-Electron Spectrometer (HADES) at GSI, using a secondary pion beam impinging on CH <inf>2</inf> and C targets. The quasi-free reaction <math altimg='si1.svg'><msup><mi>&#960;</mi><mo>&#8722;</mo></msup></math>+ p &#8239;&#8594;&#8239; n e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math> at <math altimg='si12.svg'><msqrt><msub><mi>s</mi><mrow><mi>&#960;</mi><mi mathvariant='normal'>p</mi></mrow></msub></msqrt></math> = 1.49&#8239;GeV is isolated in several analysis steps. The data set provides a crucial test for the description of baryon timelike transitions. Close to the kinematical limit the meassured e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math> mass distribution shows deviations by up to a factor 8 from the Dalitz decay of a point-like baryon. Various theoretical approaches connecting information from hadronic and electromagnetic channels in the spacelike and timelike regime compare well with the measured e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math> invariant mass distribution, including (i) a Vector Meson Dominance amplitude containing direct photon and vector meson ( <italic>&#961;</italic>) couplings to the baryon, (ii) electromagnetic timelike baryon transition form factors in a covariant spectator-quark model, where meson cloud effects dominate, and (iii) application of dispersion theory, which demonstrates the importance of the pion electromagnetic form factors.

Germany

France

R. Abou Yassine

J. Adamczewski-Musch

O. Arnold

E.T. Atomssa

M. Becker

C. Behnke

J.C. Berger-Chen

Portugal

A. Blanco

C. Blume

M. Böhmer

Czechia

L. Chlad

Poland

I. Ciepał

S. Deb

C. Deveaux

D. Dittert

J. Dreyer

E. Epple

L. Fabbietti

J. Förtsch

P. Fonte

C. Franco

J. Friese

I. Fröhlich

T. Galatyuk

Spain

J.A. Garzón

R. Gernhäuser

R. Greifenhagen

M. Grunwald

M. Gumberidze

S. Harabasz

T. Heinz

T. Hennino

C. Höhne

F. Hojeij

R. Holzmann

M. Idzik

B. Kämpfer

K-H Kampert

B. Kardan

V. Kedych

S. Kim

I. Koenig

W. Koenig

M. Kohls

J. Kolas

B.W. Kolb

G. Korcyl

G. Kornakov

R. Kotte

W. Krueger

A. Kugler

T. Kunz

R. Lalik

K. Lapidus

S. Linev

F. Linz

L. Lopes

M. Lorenz

T. Mahmoud

L. Maier

A. Malige

J. Markert

S. Maurus

V. Metag

J. Michel

D.M. Mihaylov

A. Molenda

C. Müntz

R. Münzer

M. Nabroth

L. Naumann

K. Nowakowski

A. Opíchal

J. Orliński

J.-H Otto

Cyprus

Y. Parpottas

M. Parschau

C. Pauly

V. Pechenov

O. Pechenova

K. Piasecki

J. Pietraszko

T. Povar

K. Prościński

A. Prozorov

W. Przygoda

K. Pysz

B. Ramstein

N. Rathod

P. Rodriguez-Ramos

A. Rost

A. Rustamov

P. Salabura

K. Scharmann

T. Scheib

N. Schild

K. Schmidt-Sommerfeld

H. Schuldes

E. Schwab

F. Scozzi

First measurement of massive virtual photon emission from N* baryon resonances

The existence and character of low-angular momentum quasi-bound states in 21F was probed using a (p,n) reaction. Using an active target detector, the capture excitation function for 20O + 1H was measured for the first time. Near the barrier, the capture cross section manifests an oscillatory behavior with broad peaks &#8239;&#8764;&#8239;50&#8211;100 keV wide. The presence of these peaks reflects the existence of one or more low-angular-momentum states in the quasi-bound regime. One-channel coupled channel (CC) calculations, which account only for the ground state density distributions of the colliding nuclei, show reasonable agreement with the excitation function. However, they overpredict the experimental cross section at the lowest energies measured and fail to reproduce the experimentally observed oscillations. Inclusion of the first excited 2 <math altimg='si1.svg'><msup><mrow /><mo>+</mo></msup></math> state in 20O in R-matrix (CC) calculations does produce an oscillatory behavior that roughly reproduces the observed oscillations both in magnitude and position. This result suggests that the quasi-bound state in 21F may share the vibrational character of the 2 <math altimg='si1.svg'><msup><mrow /><mo>+</mo></msup></math> state in 20O and possibly be coupled to it.

H. Desilets

Rohit Kumar

R.T. deSouza

S. Hudan

C. Ciampi

A. Chbihi

K.W. Brown

India

Varinderjit Singh

Brazil

B. Pinheiro

J.L. Ferreira

J. Lubian

Observation of oscillations and near-barrier suppression in proton capture by 20O

We compute the potential-graviton contributions to the conservative scattering angle of two nonspinning bodies in maximal supergravity at fifth order in Newton’s constant, including second-order self-force effects. Our goal is to tackle the challenging integrals arising at this order in Einstein gravity, but within the technically simpler framework of supergravity. The calculation employs the scattering-amplitude framework, effective field theory, and multiloop integration techniques based on integration by parts and differential equations. The final result is expressed as a series expansion around the static limit, thereby avoiding the explicit evaluation of intricate special functions. This series solution for the master integrals applies, as well, to the corresponding computation in general relativity. Remarkably, we observe nontrivial cancellations among contributions associated with Calabi-Yau integrals, alongside a distinct contribution governed by a Heun differential equation.

Zvi Bern

Enrico Herrmann

Switzerland

Radu Roiban

Michael S. Ruf

Alexander V. Smirnov

Vladimir A. Smirnov

United Kingdom

Mao Zeng

Second-Order Self-Force Potential-Region Binary Dynamics at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mrow><mi>G</mi></mrow><mrow><mn>5</mn></mrow></msup><mo stretchy="false">)</mo></mrow></math> in Supergravity

We study the $\textit{O}$($\textit{N}$) vector model for scalars with quartic interaction at large $\textit{N}$ on $\textit{S}$ × $\textit{S}$ without the singlet constraint. The non-trivial fixed point of the model is described by a thermal mass satisfying the gap equation at large $\textit{N}$. We obtain the free energy and the energy density for the model as a series at low temperature in units of the radius of the sphere. We show these results agree with the Borel-Padé extrapolations of the high temperature expansions of the free energy and energy density obtained in our previous work. This agreement validates both the expansions and demonstrates that low temperature expansions obtained here correspond to the same solution of the gap equation studied earlier at high temperature. We obtain the ratio of the free energy of the theory at the non-trivial fixed point to that of the Gaussian theory at all values of temperature. This ratio begins at 4/5 when the temperature is infinity, decreases to a minimum value of 0.760753, then increases and approaches unity as the temperature is decreased.

Justin David

Srijan Kumar

High to low temperature: $\textit{O}$($\textit{N}$) model at large $\textit{N}$

We explore light-ray operators in the critical O($\textit{N}$) model in the large-$\textit{N}$ limit, focusing on leading-twist and leading “horizontal” trajectories. We distinguish between light-ray operators in two conformal frames: detector operators, which characterize event shapes of final states, and distribution operators, which probe initial-state distributions. In particular, we identify parton distribution functions (PDFs) and collinear functions as matrix elements of appropriate distribution operators. We renormalize some simple detector operators at leading order in 1/$\textit{N}$, allowing us to extract the Regge intercept and the anomalous spin of the leading horizontal trajectory. We furthermore renormalize distribution versions of these operators, obtaining the leading-twist splitting function and a BFKL-type kernel, which match results from the detector frame. Finally, we show how these results can be read off from OPE data encoded in the Bethe-Salpeter resummation of conformal four-point functions.

Yue-Zhou Li

David Simmons-Duffin

Regge trajectories, detectors, and distributions in the critical O($\textit{N}$) model

We compute $$ \mathcal{O}\left({\alpha}^2Z\right) $$ radiative corrections to superallowed $\textit{β}$ decays with a heavy-particle effective field theory that systematically describes the interactions of low-energy ultrasoft photons with nuclei. We calculate two-loop virtual and one-loop real-virtual amplitudes by reducing the Feynman integrals to a set of master integrals, which we solve analytically using a variety of techniques. These techniques can be applied to other phenomenologically interesting observables. The ultrasoft corrections can then be combined with contributions arising from the exchange of potential photons to obtain the complete $$ \mathcal{O}\left({\alpha}^2Z\right) $$ correction to the decay rate, with resummation of large logarithms of the electron energy times the nuclear radius. We find that $$ \mathcal{O}\left({\alpha}^2Z\right) $$ ultrasoft loops induce a relative correction to the decay rate that ranges from 0.7 ∙ 10 in the decay of C to 3.6 ∙ 10 in the decay of Co, and will thus impact the extraction of $\textit{V}$ at the permille level. We show that the inclusion of these corrections reduces the residual renormalization scale dependence of the decay rate to a negligible level, making missing ultrasoft perturbative corrections a subdominant source of theoretical uncertainty.

Ò. Crosas

E. Mereghetti

Radiative corrections to superallowed beta decays at $$ \mathcal{O}\left({\alpha}^2Z\right) $$

Using the improved string-melting version of a Multi-Phase Transport model, we investigated the impact of nuclear geometry of 16O on anisotropic flows in O+O collisions at <math altimg='si1.svg'><mrow><msqrt><msub><mi>s</mi><msub><mrow /><mrow><mrow><mi mathvariant='normal'>N</mi></mrow><mi>N</mi></mrow></msub></msub></msqrt><mo linebreak='goodbreak'>=</mo><mn>200</mn></mrow></math> GeV. To evaluate the influence of nuclear structure and potential alpha clustering, we implemented four candidate configurations: Woods-Saxon, tetrahedron, square, and Nuclear Lattice Effective Field Theory. Initial-state geometry is quantified via the eccentricity cumulant ratio &#949; <inf>2</inf>{4}/&#949; <inf>2</inf>{2}, which provides a robust and evolution-independent measure sensitive to configuration differences. The model reproduces <italic>v</italic> <inf>2</inf>( <italic>p</italic> <inf>T</inf>) at low <italic>p</italic> <inf>T</inf> and <italic>v</italic> <inf>3</inf>( <italic>p</italic> <inf>T</inf>) across the full <italic>p</italic> <inf>T</inf> range, with integrated <italic>v</italic> <inf>2</inf>{2} and <italic>v</italic> <inf>3</inf>{2} matching the STAR data, demonstrating that transport dynamics captures the essential collectivity in this intermediate-size system. These findings establish a baseline for extending nuclear-structure studies in O+O collisions to other energies and differential observables within a unified transport model framework.

China

Xin-Li Zhao

Zi-Wei Lin

Denmark

You Zhou

Chao Zhang

Guo-Liang Ma

Nuclear cluster structure effect in 16O+ 16O collisions at the top RHIC energy