We investigate Λ production in the ( <math altimg='si146.svg'><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, <math altimg='si3.svg'><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>) reaction on a 6Li target at <math altimg='si4.svg'><msub><mrow><mi>p</mi></mrow><mrow><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></mrow></msub><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>1.05</mn></math> GeV/ <italic>c</italic>, using the distorted-wave impulse approximation (DWIA) with the Fermi-averaged <math altimg='si5.svg'><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup><mi>n</mi><mo stretchy='false'>&#8594;</mo><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup><mi mathvariant='normal'>&#923;</mi></math> amplitudes. The calculated spectrum is in good agreement with the experimental data, suggesting that <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math>- <italic>d</italic> configurations play a key role in describing the &#923; continuum states of <math altimg='si23.svg'><msubsup><mrow /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>6</mn></mrow></msubsup></math>Li near and above the <math altimg='si8.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><none /><mrow><mn>3</mn></mrow></mmultiscripts><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mi>d</mi><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mi mathvariant='normal'>&#923;</mi></math> threshold. Our analysis shows that the <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math> hypernucleus as a hyperfragment is prominently produced through <italic>D</italic>-wave resonances with <math altimg='si9.svg'><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi></mrow></msup><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msup><mrow><mn>3</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, <math altimg='si10.svg'><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, and <math altimg='si11.svg'><msup><mrow><mn>1</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> in the <math altimg='si108.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mi>d</mi></math> channel at a large momentum transfer <math altimg='si13.svg'><mi>q</mi><mo>&#8771;</mo><mn>360</mn></math>&#8211;400 MeV/ <italic>c</italic>. These findings provide theoretical evidence for the production of a <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math> hyperfragment via a cluster-like mechanism in the 6Li( <math altimg='si146.svg'><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, <math altimg='si3.svg'><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>) reaction.

Japan

Toru Harada

Yoshiharu Hirabayashi

Evidence for <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math> hyperfragment production in the 6Li( <italic>&#960;</italic> +, <italic>K</italic> +) reaction

Observations of anomalous angular correlations in electron-positron pairs produced from excited states of <math xmlns="http://www.w3.org/1998/Math/MathML"><mmultiscripts><mi>He</mi><mprescripts></mprescripts><none></none><mn>4</mn></mmultiscripts><mo>,</mo><mo> </mo><mmultiscripts><mi>Be</mi><mprescripts></mprescripts><none></none><mn>8</mn></mmultiscripts></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><mmultiscripts><mi mathvariant="normal">C</mi><mprescripts></mprescripts><none></none><mn>12</mn></mmultiscripts></math> nuclei have been suggested as being due to the creation and subsequent decay of a new light particle of mass <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>∼</mo><mn>17</mn><mspace width="0.16em"></mspace><mi>MeV</mi></mrow></math>. In this work, we investigate the possibility that the source of the observed signals is a set of new excitation channels created by the 12-quark hidden-color Fock state within the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mmultiscripts><mi>He</mi><mprescripts></mprescripts><none></none><mrow><mn>4</mn></mrow></mmultiscripts></mrow></math> nuclear wave function dubbed the “hexadiquark.” We calculate the invariant <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></mrow></math> mass spectrum for the electromagnetic transition from a new excitation of <math xmlns="http://www.w3.org/1998/Math/MathML"><mmultiscripts><mi>He</mi><mprescripts></mprescripts><none></none><mn>4</mn></mmultiscripts></math>, estimating its differential and total decay width. We find that we can fit the shape of the anomalous signal with the QCD Fock state at excitation energy <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>E</mi><mo>*</mo></msup><mo>=</mo><mn>17.9</mn><mo>±</mo><mn>1</mn><mspace width="0.16em"></mspace><mi>MeV</mi></mrow></math> and a Gaussian form factor for the electromagnetic decay. We address the physical issues with the fit parameters using properties of the hexadiquark state, in particular the three weakly repulsive <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mn>6</mn><mi>C</mi></msub></math> interactions of <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>SU</mi><mo>(</mo><mn>3</mn><mo>)</mo></mrow><mi>C</mi></msub></math> between diquark pairs. Experimental tests of our model are described in detail. In light of this work, we emphasize the need for independent experimental confirmation or refutation of the ATOMKI results as well as dedicated experiments to search for the proposed new excitations of <math xmlns="http://www.w3.org/1998/Math/MathML"><mmultiscripts><mi>He</mi><mprescripts></mprescripts><none></none><mn>4</mn></mmultiscripts></math> and other <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>α</mi></math>-cluster nuclei.

United States

Valery Kubarovsky

Jennifer Rittenhouse West

Stanley J. Brodsky

Quantum chromodynamics resolution of the ATOMKI anomaly in <math xmlns="http://www.w3.org/1998/Math/MathML"><mmultiscripts><mi>He</mi><mprescripts></mprescripts><none></none><mn>4</mn></mmultiscripts></math> nuclear transitions

Superfluid <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>4</mn></mrow></mmultiscripts></mrow></math> is an ideal candidate for the direct detection of light dark matter via nuclear recoils thanks to its low nuclear mass and the possibility to reach a low-detection-energy threshold by exploiting the generated quasiparticles. The design of future detectors based on this target, such as the DELight experiment, requires a proper understanding of the formation and partitioning of the signal for different energy depositions from various sources. This work presents an overview of the physical processes involved in the energy deposition of recoiling electrons and ions, and it describes a Monte Carlo approach to the partitioning of the signal into different channels. Despite an overall good agreement with existing literature, differences in the region of interest for light dark matter searches below 200 eV are observed.

Germany

Francesco Toschi

Axel Brunold

Lea Burmeister

Klaus Eitel

Christian Enss

Eleanor Fascione

Torben Ferber

Rahel Gabriel

Lena Hauswald

Felix Kahlhoefer

Sebastian Kempf

Markus Klute

Belina von Krosigk

Sebastian Lindemann

United Kingdom

Benedikt Maier

Marc Schumann

Melih Solmaz

Kathrin Valerius

Friedrich Carl Wagner

Signal partitioning in superfluid <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mn>4</mn></mmultiscripts></mrow></math>: A Monte Carlo approach

Precise direct cosmic-ray (CR) measurements provide an important probe to study the energetic particle sources in our Galaxy, and the interstellar environment through which these particles propagate. Uncertainties on hadronic models, ion-nucleon cross sections in particular, are currently the limiting factor toward obtaining more accurate CR ion flux measurements with calorimetric space-based experiments. We present an energy-dependent measurement of the inelastic cross section of protons and helium-4 nuclei (alpha particles) on a <math><mrow><msub><mrow><mi>Bi</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math><math><msub><mtext>Ge</mtext><mn>3</mn></msub><msub><mi>O</mi><mn>12</mn></msub></math> target, using 88 months of data collected by the DAMPE space mission. The kinetic energy range per nucleon of the measurement points ranges from 18 GeV to 9 TeV for protons, and from <math><mrow><mn>5</mn><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>n</mi></mrow></math> to <math><mrow><mn>3</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi><mo>/</mo><mi>n</mi></mrow></math> for helium-4 nuclei. Our results lead to a significant improvement of the CR flux normalization. In the case of helium-4, these results correspond to the first cross section measurements on a heavy target material at energies above <math><mrow><mn>10</mn><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>n</mi></mrow></math>.

Italy

F. Alemanno

China

Q. An

Switzerland

P. Azzarello

F. C. T. Barbato

P. Bernardini

X. J. Bi

I. Cagnoli

M. S. Cai

E. Casilli

E. Catanzani

J. Chang

D. Y. Chen

J. L. Chen

Z. F. Chen

P. Coppin

M. Y. Cui

T. S. Cui

Y. X. Cui

H. T. Dai

A. De Benedittis

I. De Mitri

F. de Palma

A. Di Giovanni

Q. Ding

T. K. Dong

Z. X. Dong

G. Donvito

D. Droz

J. L. Duan

K. K. Duan

R. R. Fan

Y. Z. Fan

F. Fang

K. Fang

C. Q. Feng

L. Feng

J. M. Frieden

P. Fusco

M. Gao

F. Gargano

K. Gong

Y. Z. Gong

D. Y. Guo

J. H. Guo

S. X. Han

Y. M. Hu

G. S. Huang

X. Y. Huang

Y. Y. Huang

M. Ionica

L. Y. Jiang

Y. Z. Jiang

W. Jiang

J. Kong

A. Kotenko

D. Kyratzis

S. J. Lei

W. H. Li

W. L. Li

X. Li

X. Q. Li

Y. M. Liang

C. M. Liu

H. Liu

J. Liu

S. B. Liu

Y. Liu

F. Loparco

C. N. Luo

M. Ma

P. X. Ma

T. Ma

X. Y. Ma

G. Marsella

M. N. Mazziotta

D. Mo

X. Y. Niu

X. Pan

A. Parenti

W. X. Peng

X. Y. Peng

C. Perrina

E. Putti-Garcia

R. Qiao

J. N. Rao

A. Ruina

R. Sarkar

P. Savina

A. Serpolla

Z. Shangguan

W. H. Shen

Z. Q. Shen

Z. T. Shen

L. Silveri

J. X. Song

M. Stolpovskiy

H. Su

Hong Kong

M. Su

H. R. Sun

Z. Y. Sun

Hadronic cross section measurements with the DAMPE space mission using 20 GeV-10 TeV cosmic-ray protons and <math><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>4</mn></mrow></mmultiscripts></mrow></math>

In <math><mrow><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>3</mn></mrow></mmultiscripts></mrow><mtext>−</mtext><mi>B</mi></mrow></math>, two atoms pair in an orbital angular momentum 1 spin triplet state above the phase transition temperature with <math><mi>S</mi><mi>O</mi><mo>(</mo><mn>3</mn><mo>)</mo><mo>×</mo><mi>S</mi><mi>O</mi><mo>(</mo><mn>3</mn><mo>)</mo></math> symmetry. Below the transition temperature, this symmetry is spontaneously broken to the diagonal <math><mi>S</mi><mi>O</mi><mo>(</mo><mn>3</mn><mo>)</mo></math> due to spin-orbit coupling. Considerations based on effective potentials and solitons show that <math><mi>S</mi><mi>O</mi><mo>(</mo><mn>3</mn><mo>)</mo></math>’s get enhanced to <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo></math>’s and the symmetry breaking is that of <math><mi>G</mi><mo>=</mo><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo><mo>×</mo><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo><mo>×</mo><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></math> to <math><mi>H</mi><mo>=</mo><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo></math>. The theory of the resultant Goldstone modes can be naturally formulated as a gauge theory of <math><mi>H</mi></math>. Its Gauss law is treated here and shown to lead to surface states in a container with a dynamics governed by large gauge transformations. Observable consequences are pointed out. The transference of the analysis to the chiral model of QCD is pointed out where <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo></math> are the left and right chiral groups, <math><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></math> is the axial <math><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></math>, the surviving symmetry is flavor <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo></math>, and the Goldstone modes are the pions.

A. P. Balachandran

Non-Abelian gauge theory for surface excitations of <math><mrow><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>3</mn></mrow></mmultiscripts></mrow><mtext>−</mtext><mi>B</mi></mrow></math>

The $^{3}$He<math><msup><mrow><mo>(</mo><mi>α</mi><mo>,</mo><mi>γ</mi><mo>)</mo></mrow><mrow><mn>7</mn></mrow></msup></math>Be radiative capture reaction plays a key role in the creation of elements in stars as well as in the production of solar neutrinos, the observation of which is one of the main tools to study the properties of our sun. Since accurate experimental measurements of this fusion cross section at solar energies are difficult due to the strong Coulomb repulsion between the reactants, the onus falls on theory to provide a robust means for extrapolating from the region where experimental data is available down to the desired astrophysical regime. We present the first microscopic calculations of $^{3}$He<math><msup><mrow><mo>(</mo><mi>α</mi><mo>,</mo><mi>γ</mi><mo>)</mo></mrow><mrow><mn>7</mn></mrow></msup></math>Be with explicit inclusion of three-nucleon forces. Our prediction of the astrophysical S factor qualitatively agrees with experimental data. We further incorporate experimental bound-state and scattering information in our calculation to arrive at a more quantitative description. This process reveals that our current model lacks sufficient repulsion in the <math><mn>1</mn><mo>/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></math> channel of our model space to simultaneously reproduce elastic-scattering data. This deficit suggests that $^{3}$He<math><msup><mrow><mo>(</mo><mi>α</mi><mo>,</mo><mi>γ</mi><mo>)</mo></mrow><mrow><mn>7</mn></mrow></msup></math>Be probes aspects of the nuclear force that are not currently well-constrained.

M.C. Atkinson

K. Kravvaris

S. Quaglioni

Canada

P. Navrátil

Calculation of the He( , ) Be astrophysical S factor with chiral two- and three-nucleon forces

Deuteron-<math><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>3</mn></mrow></mmultiscripts></math> reactions in the 15 to 40 MeV range are studied using a three-body model where the constructed nonlocal optical potentials rely on rigorous nucleon-<math><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>3</mn></mrow></mmultiscripts></math> scattering calculations. The differential cross section for the elastic scattering and neutron transfer reaction is predicted quite well up to 90 deg scattering angles. The importance of the Pauli term in complex potentials is demonstrated.

Lithuania

A. Deltuva

D. Jurčiukonis

Deuteron- He scattering using nucleon- He optical potentials fitted to four-body amplitudes

We study dark matter scattering off $$ ^4$$ <math> <mmultiscripts> <mrow></mrow> <mrow></mrow> <mn>4</mn> </mmultiscripts> </math> He and other light nuclei using chiral effective field theory. We consider scalar DM interactions and include both one- and two-nucleon scattering processes. The DM interactions and nuclear wave functions are obtained from chiral effective field theory and we work up to fourth order in the chiral expansion for the latter to investigate the chiral convergence. The results for the scattering rates can be used to determine the sensitivity of planned experiments to detect relatively light dark matter particles using $$ ^4$$ <math> <mmultiscripts> <mrow></mrow> <mrow></mrow> <mn>4</mn> </mmultiscripts> </math> He. We find that next-to-leading-order scalar currents are smaller than expected from power counting for scattering off $$ ^4$$ <math> <mmultiscripts> <mrow></mrow> <mrow></mrow> <mn>4</mn> </mmultiscripts> </math> He confirming earlier work. However, the results for two-nucleon corrections exhibit a linear regulator dependence indicating potential problems in the applied power counting. We observe a linear correlation between the, in principle not observable, D-wave probability of various light nuclei and the scalar two-nucleon matrix elements, again pointing towards potentially missing contributions.

Netherlands

J. Vries

C. Körber

A. Nogga

S. Shain

Dark matter scattering off $$ ^{4}$$ <math> <mmultiscripts> <mrow></mrow> <mrow></mrow> <mn>4</mn> </mmultiscripts> </math> He in chiral effective field theory

Condensed matter materials have shown great potential in searching for light dark matter (DM) via detecting the phonon or magnon signals induced by the scattering of DM off the materials. In this paper, we study the possibility of detecting electromagnetic form factors of fermionic DM and axionlike particles (ALPs) using superfluid <math><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>4</mn></mrow></mmultiscripts></mrow></math>. The phonon induced by a sub-GeV fermionic DM scattering off the superfluid can be described using the effective field theory with the interaction between DM and the bulk <math><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>4</mn></mrow></mmultiscripts></mrow></math>. Signals arising from the electromagnetic form factors of light DM in the presence of an external electric field are calculated. Projected constraints on the charge radius, anapole moment, and magnetic moment of the DM are derived with <math><mrow><mn>1</mn><mtext> </mtext><mtext> </mtext><mi>kg</mi><mo>·</mo><mi>yr</mi></mrow></math> exposure. The phonon signal induced by the scattering of ALPs off the superfluid is also calculated, which can put competitive and the first direct detection bounds on ALP-photon-dark photon couplings in the projected experiments.

Wei Chao

Si-Chun Sun

Xin Wang

Chen-Hui Xie

Axion and dark fermion electromagnetic form factors in superfluid <math><mrow><mmultiscripts><mrow><mi>He</mi></mrow><mprescripts></mprescripts><none></none><mn>4</mn></mmultiscripts></mrow></math>

High energy states in the self-conjugate $^{16}$O nucleus were investigated by analyzing $^{13}$C($^{3}$He,α)$^{12}$C reactions in the bombarding energy range 1.4–2.2 MeV. Thanks to a low-threshold and high-resolution array, we succeed in measuring cross sections of the decay channel where an α particle is emitted in coincidence with a $^{12}$C nucleus in the Hoyle state, leading to 4α particles in the final channel. The analysis of angular distributions indicates the occurrence of two low-spin resonant states, respectively with <math><msup><mrow><mi>J</mi></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></math> and <math><msup><mrow><mn>3</mn></mrow><mrow><mo>−</mo></mrow></msup></math>, at energies of ≈ 24.1 and 24.5 MeV. In this energy window, the observed branching ratios for the transition involving the emission of the Hoyle state are well larger than calculations based on barrier penetration, signaling the possible occurrence of high-energy states in $^{16}$O with a large cluster component.

L. Redigolo

I. Lombardo

D. Dell'Aquila

M. Vigilante

M. Aytekin

L. Baldesi

S. Barlini

A. Camaiani

G. Casini

C. Ciampi

M. Cicerchia

D. Fabris

C. Frosin

F. Gramegna

T. Marchi

A. Ordine

P. Ottanelli

G. Pasquali

S. Piantelli

M. Russo

A. Stefanini

S. Valdrè

G. Verde

Clustering in high-energy excited states of O probed by He+ C reactions at low energies