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DOE OSTI2022

Dark Energy Survey Year 3 results: A 2.7% measurement of baryon acoustic oscillation distance scale at redshift 0.835

We present angular diameter measurements obtained by measuring the position of baryon acoustic oscillations (BAO) in an optimized sample of galaxies from the first three years of Dark Energy Survey data (DES Y3). The sample consists of 7 million galaxies distributed over a footprint of 4100 deg 2 with 0.6 < z photo < 1.1 and a typical redshift uncertainty of 0.03 ( 1 + z ) . The sample selection is the same as in the BAO measurement with the first year of DES data, but the analysis presented here uses three times the area, extends to higher redshift, and makes a number of improvements, including a fully analytical BAO template, the use of covariances from both theory and simulations, and an extensive preunblinding protocol. We used two different statistics; angular correlation function and power spectrum, and validate our pipeline with an ensemble of over 1500 realistic simulations. Both statistics yield compatible results. We combine the likelihoods derived from angular correlations and spherical harmonics to constrain the ratio of comoving angular diameter distance D M at the effective redshift of our sample to the sound horizon scale at the drag epoch. We obtain D M ( z eff = 0.835 ) / r d = 18.92 ± 0.51 , which is consistent with, but smaller than, the Planck prediction assuming flat Λ CDM , at the level of 2.3 σ . The analysis was performed blind and is robust to changes in a number of analysis choices. It represents the most precise BAO distance measurement from imaging data to date, and is competitive with the latest transverse ones from spectroscopic samples at z > 0.75 . When combined with DES 3 x 2 pt + SNIa , they lead to improvements in H 0 and Ω m constraints by ∼ 20 % .

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2022

Dark Energy Survey Year 3 results: Measurement of the baryon acoustic oscillations with three-dimensional clustering

The three-dimensional correlation function offers an effective way to summarize the correlation of the large-scale structure even for imaging galaxy surveys. We have applied the projected three-dimensional correlation function, ξ p to measure the baryonic acoustic oscillations (BAO) scale on the first-three years Dark Energy Survey data. The sample consists of about 7 million galaxies in the redshift range 0.6< z p < 1.1 over a footprint of 4108 deg 2 . Our theory modeling includes the impact of realistic true redshift distributions beyond Gaussian photo-z approximation. ξ p is obtained by projecting the three-dimensional correlation to the transverse direction. To increase the signal-to-noise of the measurements, we have considered a Gaussian stacking window function in place of the commonly used top-hat. ξ p is sensitive to D M (z eff )/r s , the ratio between the comoving angular diameter distance and the sound horizon. Using the full sample, D M (z eff )/r s is constrained to be19.00 ± 0.67 (top-hat) and 19.15 ± 0.58 (Gaussian) at z eff = 0.835. The constraint is weaker than the angular correlation w constraint 18.84 ± 0.50), and we trace this to the fact that the BAO signals are heterogeneous across redshift. While ξ p responds to the heterogeneous signals by enlarging the error bar, w can still give a tight bound on D M s in this case. When a homogeneous BAO-signal subsample in the range 0.7 < z p <1.0 (z eff = 0.845) is considered, ξp yields 19.80 ± 0.67 (top-hat) and 19.84 ± 0.53 (Gaussian). The latter is mildly stronger than the w constraint (19.86 ± 0.55). We find that the ξ p results are more sensitive to photo-z because ξ p keeps the three-dimensional clustering information causing it to be more prone to photo-z noise. The Gaussian window gives more robust results than the top-hat as the former is designed to suppress the low signal modes. ξ p and the angular statistics such as w have their own pros and cons, and they serve an important crosscheck with each other.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2023

Preparations for quantum simulations of quantum chromodynamics in 1+1 dimensions. II. Single-baryon β-decay in real time

Here, a framework for quantum simulations of real-time weak decays of hadrons and nuclei in a two-flavor lattice theory in one spatial dimension is presented. A single generation of the Standard Model is found to require 16 qubits per spatial lattice site after mapping to spin operators via the Jordan-Wigner transformation. Both quantum chromodynamics and flavor-changing weak interactions are included in the dynamics, the latter through four-Fermi effective operators. Quantum circuits that implement time evolution in this lattice theory are developed and run on Quantinuum’s H1-1 20-qubit trapped ion system to simulate the β-decay of a single baryon on one lattice site. These simulations include the initial state preparation and are performed for both one and two Trotter time steps. The potential intrinsic error-correction properties of this type of lattice theory are discussed, and the leading lattice Hamiltonian required to simulate 0νββ-decay of nuclei induced by a neutrino Majorana mass term is provided.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2023

Search for the baryon- and lepton-number violating decays B 0 → pμ⁻ and $B^0_s$ → pμ⁻

A search for the baryon- and lepton-number violating decays and $B$$^{0}_{s}$ →pμ – is performed at the LHCb experiment using data collected in proton-proton collisions at √s =7, 8 and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6 fb –1 , respectively. No significant signal for B 0 → p⁢μ – and $B$$^{0}_{s}$ → p⁢μ – decays is found and the upper limits on the branching fractions are determined to be Β⁡(B 0 → pμ – ) < 2.6⁢(3.1) ×10 –9 and Β($B$$^{0}_{s}$ → pμ – ) < 12.1⁢(14.0) ×10 –9 , respectively, at 90% (95%) confidence level. These are the first limits on these decays to date.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Baryons and tetraquarks using instanton-induced interactions

We analyze some aspects of the perturbative and nonperturbative interactions in the composition of heavy quarkonia, heavy and light baryons ( c c c and u u u ones), as well as all charm tetraquarks ( c c c ¯ c ¯ ). Using the hyperspherical approximation and effective radial potentials (in six and nine dimensions, respectively) we derive their spectra and wave functions. In all of the cases, we focus on the splittings between the S -shell levels, which are remarkably insensitive to the quark masses, but proportional to the effective interaction potentials. We use the traditional Cornell-like potentials, and the nonperturbative instanton-induced static potentials, from correlators of two, three, and four Wilson lines, and find rather satisfactory description of spectra in all cases. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

Search for baryon and lepton number violating decays D → p ℓ

We search for the baryon and lepton number violating charm decays, D → p ℓ , where D is either a D 0 or a D ¯ 0 and ℓ is a muon or an electron, using a data sample of 921 fb − 1 collected by the Belle detector at the KEKB asymmetric energy e + e − collider. In the absence of significant signals, we set upper limits on the branching fractions in the range ( 5 – 8 ) × 10 − 7 at a 90% confidence level, depending on the decay mode. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

Measurement of Ω c 0 baryon production and branching-fraction ratio BR ( Ω c 0 → Ω - e + ν e ) / BR ( Ω c 0 → Ω - π + ) in p p collisions at s = 13 TeV

The inclusive production of the charm-strange baryon $Ω^0_c$ is measured for the first time via its semileptonic decay into $Ω$ - e + ν e at midrapidity (|y| < 0.8) in proton-proton (pp) collisions at the center-of mass energy $\sqrt{s}$ = 13 TeV with the ALICE detector at the LHC. The transverse momentum (p T ) differential cross section multiplied by the branching ratio is presented in the interval 2 < p T < 12 GeV=c. The branching-fraction ratio BR($Ω^0_c$ → $Ω$ - e + ν e )/BR($Ω^0_c$→ Ω - π + ) is measured to be 1.12 ± 0.22 (stat) ± 0.27 (syst). Comparisons with other experimental measurements, as well as with theoretical calculations, are presented

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Search for charmed baryons in the Λ c + η system and measurement of the branching fractions of Λ c ( 2880 ) + and Λ c ( 2940 ) + decaying to Λ c + η and p D 0 relative to Σ c ( 2455 ) π

We search for excited charmed baryons in the Λ c + η system using a data sample corresponding to an integrated luminosity of 980 fb − 1 . The data were collected by the Belle detector at the KEKB e + e − asymmetric-energy collider. No significant signals are found in the Λ c + η mass spectrum, including the known Λ c ( 2880 ) + and Λ c ( 2940 ) + . Clear Λ c ( 2880 ) + and Λ c ( 2940 ) + signals are observed in the p D 0 mass spectrum. We set upper limits at 90% credibility level on ratios of branching fractions of Λ c ( 2880 ) + and Λ c ( 2940 ) + decaying to Λ c + η relative to Σ c ( 2455 ) π of < 0.13 for the Λ c ( 2880 ) + and < 1.11 for the Λ c ( 2940 ) + . We measure ratios of branching fractions of Λ c ( 2880 ) + and Λ c ( 2940 ) + decaying to p D 0 relative to Σ c ( 2455 ) π of 0.75 ± 0.03 ( stat ) ± 0.07 ( syst ) for the Λ c ( 2880 ) + and 3.59 ± 0.21 ( stat ) ± 0.56 ( syst ) for the Λ c ( 2940 ) + . Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

Dark Energy Survey: Galaxy sample for the baryonic acoustic oscillation measurement from the final dataset

In this paper, we present and validate the galaxy sample used for the analysis of the baryon acoustic oscillation (BAO) signal in the Dark Energy Survey (DES) Y6 data. The definition is based on a color and redshift-dependent magnitude cut optimized to select galaxies at redshifts higher than 0.6, while ensuring a high-quality photo- z determination. The optimization is performed using a Fisher forecast algorithm, finding the optimal i -magnitude cut to be given by i < 19.64 + 2.894 z ph . For the optimal sample, we forecast an increase in precision in the BAO measurement of ∼ 25 % with respect to the Y3 analysis. Our BAO sample has a total of 15,937,556 galaxies in the redshift range 0.6 < z ph < 1.2 , and its angular mask covers 4 , 273.42 deg 2 to a depth of i = 22.5 . We validate its redshift distributions with three different methods: directional neighborhood fitting algorithm (DNF), which is our primary photo- z estimation; direct calibration with spectroscopic redshifts from VIPERS, which is a spectroscopic galaxy sample that overlaps with our BAO sample and is complete within our selection cuts; and clustering redshift using SDSS galaxies. The fiducial redshift distribution is a combination of these three techniques performed by modifying the mean and width of the DNF distributions to match those of VIPERS and clustering redshift. In this paper, we also describe the methodology used to mitigate the effect of observational systematics, which is analogous to the one used in the Y3 analysis. This paper is one of the two dedicated to the analysis of the BAO signal in DES Y6. In its companion paper, we present the angular diameter distance constraints obtained through the fitting to the BAO scale.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2024

Dark Energy Survey: A 2.1% measurement of the angular baryonic acoustic oscillation scale at redshift z eff = 0.85 from the final dataset

Here, we present the angular diameter distance measurement obtained with the baryonic acoustic oscillation (BAO) feature from galaxy clustering in the completed Dark Energy Survey, consisting of six years (Y6) of observations. We use the Y6 BAO galaxy sample, optimized for BAO science in the redshift range 0.6 < z <1.2, with an effective redshift at z eff = 0.85 and split into six tomographic bins. The sample has nearly 16 million galaxies over 4,273 square degrees. Our consensus measurement constrains the ratio of the angular distance to sound horizon scale to D M ⁡(z eff )/r d = 19.51 ± 0.41 (at 68.3% confidence interval), resulting from comparing the BAO position in our data to that predicted by planck Λ⁢CDM via the BAO shift parameter α =(D M /r d )/(D M /r d ) PLANCK . To achieve this, the BAO shift is measured with three different methods, angular correlation function (ACF), angular power spectrum (APS), and projected correlation function (PCF), obtaining α = 0.952 ± 0.023, 0.962 ± 0.022, and 0.955 ± 0.020, respectively, which we combine to α = 0.957 ± 0.020, including systematic errors. When compared with the Λ⁢CDM model that best fits planck data, this measurement is found to be 4.3% and 2.1⁢σ below the angular BAO scale predicted. To date, it represents the most precise angular BAO measurement at z > 0.75 from any survey and the most precise measurement at any redshift from photometric surveys. The analysis was performed blinded to the BAO position, and it is shown to be robust against analysis choices, data removal, redshift calibrations, and observational systematics.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2024

Search for the baryon number and lepton number violating decays τ − → Λ π − and τ − → Λ ¯ π − at Belle II

We present a search for the baryon number B and lepton number L violating decays τ − → Λ π − and τ − → Λ ¯ π − produced from the e + e − → τ + τ − process, using a 364 fb − 1 data sample collected by the Belle II experiment at the SuperKEKB collider. No evidence of signal is found in either decay mode, which have | Δ ( B − L ) | equal to 2 and 0, respectively. Upper limits at 90% credibility level on the branching fractions of τ − → Λ π − and τ − → Λ ¯ π − are determined to be 4.7 × 10 − 8 and 4.3 × 10 − 8 , respectively. Published by the American Physical Society 2024

Adachi, I. (ORCID:0000000322870173)↗

DOE OSTI2020

Implications of the Upper Bound on h → μ + μ - on the Baryon Asymmetry of the Universe

The upper bounds from the ATLAS and CMS experiments on the decay rate of the Higgs boson to two muons provide the strongest constraint on an imaginary part of the muon Yukawa coupling. This bound is more than an order of magnitude stronger than bounds from $\mathcal{CP}$-violating observables, specifically the electric dipole moment of the electron. It excludes a scenario $-$ which had been viable prior to these measurements $-$ that a complex muon Yukawa coupling is the dominant source of the baryon asymmetry. Even with this bound, the muon source can still contribute ${\cal O}(16\%)$ of the asymmetry.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Observation of Cabibbo-Suppressed Two-Body Hadronic Decays and Precision Mass Measurement of the Ω c 0 Baryon

The first observation of the singly Cabibbo-suppressed Ω c 0 → Ω − K + and Ω c 0 → Ξ − π + decays is reported, using proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb − 1 , collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to be B ( Ω c 0 → Ω − K + ) B ( Ω c 0 → Ω − π + ) = [ 6.08 ± 0.51 ( stat ) ± 0.40 ( syst ) ] % , B ( Ω c 0 → Ξ − π + ) B ( Ω c 0 → Ω − π + ) = [ 15.81 ± 0.87 ( stat ) ± 0.44 ( syst ) ± 0.16 ( ext ) ] % . In addition, using the Ω c 0 → Ω − π + decay channel, the Ω c 0 baryon mass is measured to be M ( Ω c 0 ) = 2695.28 ± 0.07 ( stat ) ± 0.27 ( syst ) ± 0.30 ( ext ) MeV , improving the precision of the previous world average by a factor of 4. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗

DOE OSTI2024

Enhanced Production of Λ b 0 Baryons in High-Multiplicity p p Collisions at s = 13 TeV

The production rate of Λ b 0 baryons relative to B 0 mesons in p p collisions at a center-of-mass energy s = 13 TeV is measured by the LHCb experiment. The ratio of Λ b 0 to B 0 production cross sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e + e − collisions, and increases by a factor of ∼ 2 with increasing multiplicity. At relatively low transverse momentum, the ratio of Λ b 0 to B 0 cross sections is higher than what is measured in e + e − collisions, but converges with the e + e − ratio as the momentum increases. These results imply that the evolution of heavy b quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with several models and implications for the mechanisms enforcing quark confinement are discussed. © 2024 CERN, for the LHCb Collaboration 2024 CERN

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2024

New Probe of the High- z Baryon Acoustic Oscillation Scale: BAO Tomography with CMB × LIM -Nulling Convergence

Standard rulers such as the baryon acoustic oscillation (BAO) scale serve as workhorses for precision tests of cosmology, enabling distance measurements that probe the geometry and expansion history of our Universe. Aside from BAO measurements from the cosmic microwave background (CMB), most standard ruler techniques operate at relatively low redshifts and depend on biased tracers of the matter density field. In a companion paper, we explored the scientific reach of nulling estimators, where CMB lensing convergence maps are cross-correlated with linear combinations of similar maps from line intensity mapping (LIM) to precisely null out the low-redshift contributions to CMB lensing. We showed that nulling estimators can be used to constrain the high redshift matter power spectrum and showed that this spectrum exhibits discernible BAO features. Here we propose using these features as a standard ruler at high redshifts that does not rely on biased tracers. Forecasting such a measurement at z ~ 5, we find that next-generation instruments will be able to constrain the BAO scale to 7.2% precision, while our futuristic observing scenario can constrain the BAO scale to 4% precision. In conclusion, this constitutes a fundamentally new kind of BAO measurement during early epochs in our cosmic history.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2026

High-precision scale setting with the Ω-baryon mass and gradient flow

The gradient-flow scale 𝑤 0 in lattice QCD is determined using the mass of the Ω − baryon to set the physical scale. Nine ensembles using the highly improved staggered quark (HISQ) action with lattice spacings of 0.15 fm down to 0.04 fm are used, seven of which have nearly physical light-quark masses. Electromagnetic corrections to the Ω − mass are defined in order to compute a pure-QCD Ω mass. The final result is 𝑤 0 = 0.17187⁢(68) fm, corresponding to a relative uncertainty of 0.40% and a central value in good agreement with previous calculations in the literature.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2025

Apparent 𝑤 <−1 and a Lower 𝑆 8 from Dark Axion and Dark Baryons Interactions

We show that a simple coupling between dark energy and dark matter can simultaneously address two distinct hints at new physics coming from cosmological observations. The first is the recent evidence from the DESI project and supernovae observations that the dark energy equation of state w is evolving over cosmic time from an earlier value that is <-1 to a present-day value >-1. The second observation is the so-called S8 tension, describing the suppression of the growth of matter overdensities compared to that expected in the ΛCDM model. Here, we propose a stable, technically natural particle physics implementation of this idea, in which dark matter consists of dark baryons in a strongly coupled hidden sector, and the dark energy field is the associated dark axion. The time variation of the dark matter mass results in an effective dark energy equation of state that exhibits a phantom crossing behavior consistent with recent results. It also results in a slight delay in matter-radiation equality, which suppresses the overall growth of density perturbations.

Axions↗

DOE OSTI2026

DESI DR2 Baryon Acoustic Oscillations from the Lyman Alpha Forest Multipoles

We present an alternative measurement of the Baryon Acoustic Oscillation (BAO) using the Legendre multipole representation of the Ly$α$ forest correlation functions from the second data release (DR2) of the Dark Energy Spectroscopic Instrument survey. Compressing the auto- and cross-correlation functions into Legendre multipoles yields a positive-definite covariance matrix without any smoothing -- unlike the baseline DR2 analysis -- thanks to a significantly reduced data vector size. We introduce the statistical corrections required to debias the finite-sample covariance matrix estimate and demonstrate that monopole and quadrupole terms for both auto- and cross-correlations can be used even when the correlation functions are distorted by continuum errors and contaminated by metals. This formalism has slightly diminished the constraining power of the BAO scale, while considerably weakening constraints on nuisance parameters. We measure the isotropic BAO scale with $0.93\%$ precision at $z_\mathrm{eff}=2.35$, the Hubble parameter $H(z_\mathrm{eff})=(239.5\pm3.4)~(147.09~\mathrm{Mpc}/r_d) ~\mathrm{km~s}^{-1}~\text{Mpc}^{-1}$, and the transverse comoving distance $D_M(z_\mathrm{eff})=(5.80 \pm 0.10)~(r_d/147.09~\mathrm{Mpc})$~Gpc for a given value of the sound horizon ($r_d$). Our BAO results are entirely consistent with the baseline DR2 analysis.