Observation of the Radiative Decays of Υ ( 1 S ) to χ c 1
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46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
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An improved direct limit on the muon electric dipole moment
A limit on the permanent electric dipole moment (EDM) of the positive muon is presented based on data from the Fermilab Muon g-2 Experiment taken between 2019 and 2020. The tracking detectors measure the average vertical decay angle of positrons from muon decays, enabling a search for an interaction between a possible muon EDM $d_μ$ and the lab-frame magnetic field. The result, $d_μ= (-0.35 \pm 0.19_{\mathrm{stat}} \pm 0.34_{\mathrm{sys}}) \times10^{-19}~e\cdot$cm, is consistent with zero and sets a new direct limit on the muon EDM of $|d_μ|<1.10\times10^{-19}~e\cdot$cm at the 95 percent confidence level.
Aguillard, D. P. [Michigan U.] (ORCID:000000025556↗
Axion Dark Matter
Axions are well-motivated dark matter candidates with simple cosmological production mechanisms. They were originally introduced to solve the strong CP problem, but also arise in a wide range of extensions to the Standard Model. This Snowmass white paper summarizes axion phenomenology and outlines next-generation laboratory experiments proposed to detect axion dark matter. There are vibrant synergies with astrophysical searches and advances in instrumentation including quantum-enabled readout, high-Q resonators and cavities and large high-field magnets. This white paper outlines a clear roadmap to discovery, and shows that the US is well-positioned to be at the forefront of the search for axion dark matter in the coming decade.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Evidence of h b ( 2 P ) → ϒ ( 1 S ) η Decay and Search for h b ( 1 P , 2 P ) → ϒ ( 1 S ) π 0 with the Belle Detector
We report the first evidence for the h b ( 2 P ) → ϒ ( 1 S ) η transition with a significance of 3.5 standard deviations. The decay branching fraction is measured to be B [ h b ( 2 P ) → ϒ ( 1 S ) η ] = ( 7.1 − 3.2 + 3.7 ± 0.8 ) × 10 − 3 , which is noticeably smaller than expected. We also set upper limits on π 0 transitions of B [ h b ( 2 P ) → ϒ ( 1 S ) π 0 ] < 1.8 × 10 − 3 , and B [ h b ( 1 P ) → ϒ ( 1 S ) π 0 ] < 1.8 × 10 − 3 , at the 90% confidence level. These results are obtained with a 131.4 fb − 1 data sample collected near the ϒ ( 5 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. Published by the American Physical Society 2024
Kovalenko, E. (ORCID:0000000180841931)↗
Search for a dark leptophilic scalar produced in association with τ + τ − pair in e + e − annihilation at center-of-mass energies near 10.58 GeV
A dark leptophilic scalar ( ϕ L ) is a hypothetical particle that couples only to leptons rather than quarks. We report on a search for ϕ L in the e + e − → τ + τ − ϕ L , ϕ L → ℓ + ℓ − ( ℓ = e , μ ) process using 626 fb − 1 of data collected by the Belle experiment near the ϒ ( 4 S ) resonance. We validate the backgrounds with multiple control regions in data, using a novel multiclass multivariate event classifier. In absence of a signal, we quote upper limits at the 90% confidence level on the coupling between ϕ L and leptons. Our bounds, obtained in a blinded approach, are 19% more constraining than the previous limits, averaged over the mass range 0.04 ≤ m ϕ L ≤ 6.5 GeV . We exclude the parameter space below 4 GeV favored by measurement of the anomalous magnetic moment of the muon. Published by the American Physical Society 2024
Biswas, D. (ORCID:0000000275433471)↗
Measurement of the time-integrated C P asymmetry in D 0 → K S 0 K S 0 decays using Belle and Belle II data
We measure the time-integrated C P asymmetry in D 0 → K S 0 K S 0 decays reconstructed in e + e − → c c ¯ events collected by the Belle and Belle II experiments. The corresponding data samples have integrated luminosities of 980 and 428 fb − 1 , respectively. The D 0 decays are required to originate from the D * + → D 0 π + decay, which determines the charm flavor at production time. A control sample of D 0 → K + K − decays is used to correct for production and detection asymmetries. The result, ( − 1.4 ± 1.3 ( stat ) ± 0.1 ( syst ) ) % , is consistent with previous determinations and with C P symmetry. Published by the American Physical Society 2025
Adachi, I. (ORCID:0000000322870173)↗
Evidence of a New Excited Charmed Baryon Decaying to Σ c ( 2455 ) 0 , + + π ±
We present the study of $\overline{B}$ 0 →Σ c (2455) 0,++ π ± $\overline{p}$ decays based on 772×10 6 B$\overline{B}$ events collected with the Belle detector at the KEKB asymmetric-energy e + e - collider. The Σ c (2455) 0,++ candidates are reconstructed via their decay to Λ$^{+}_{c}$π ∓ and Λ$^{+}_{c}$ decays to pK - π + , pK$^{0}_{S}$, and Λπ + final states. The corresponding branching fractions are measured to be $\mathscr{B}$($\overline{B}$ 0 →Σ c (2455) 0 π + $\overline{p}$)=(1.09±0.06±0.07)×10 -4 and $\mathscr{B}$($\overline{B}$ 0 →Σ c (2455) ++ π - $\overline{p}$)=(1.84±0.11±0.12)×10 -4 , which are consistent with the world average values with improved precision. A new structure is found in the M Σ c (2455) 0,++π± spectrum with a significance of 4.2σ including systematic uncertainty. The structure is possibly an excited Λ$^{+}_{c}$ and is tentatively named Λ c (2910) + . Its mass and width are measured to be (2913.8±5.6±3.8) MeV/c 2 and (51.8±20.0±18.8) MeV, respectively. The products of branching fractions for the Λ c (2910) + are measured to be $\mathscr{B}$($\overline{B}$ 0 →Λ c (2910) + $\overline{p}$) × $\mathscr{B}$(Λ c (2910) + →Σ c (2455) 0 π + )=(9.5±3.6±1.6) x 10 -6 and $\mathscr{B}$($\overline{B}$ 0 →Λ c (2910) + $\overline{p}$) × $\mathscr{B}$(Λ c (2910) + →Σ c (2455 )++ π - )=(1.24±0.35±0.10)×10 -5 . Here, the first and second uncertainties are statistical and systematic, respectively.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Measurement of branching fractions of Λ$^+_c$ → pK$^0_S$K$^0_S$ and Λ$^+_c$ → pK$^0_S$η at Belle
We present a study of a singly Cabibbo-suppressed decay Λ$^+_c$ → pK$^0_S$K$^0_S$ and a Cabibbo-favored decay Λ$^+_c$ → pK$^0_S$η based on 980 fb -1 of data collected by the Belle detector, operating at the KEKB energy-asymmetric e + e - collider. We measure their branching fractions relative to Λ$^+_c$ → pK$^0_S$: $\mathscr{B}$(Λ$^+_c$ → pK$^0_S$K$^0_S$)/$\mathscr{B}$(Λ$^+_c$ → pK$^0_S$) = (1.48 ± 0.08 ± 0.04) × 10 -2 and $\mathscr{B}$(Λ$^+_c$ → pK$^0_S$η)/$\mathscr{B}$(Λ$^+_c$ → pK$^0_S$) = (2.73 ± 0.06 ± 0.13) × 10 -1 . Combining with the world average $\mathscr{B}$(Λ$^+_c$ → pK$^0_S$), we have the absolute branching fractions, $\mathscr{B}$(Λ$^+_c$ → pK$^0_S$K$^0_S$) = (2.35 ± 0.12 ± 0.07 ± 0.12) × 10 -4 and $\mathscr{B}$(Λ$^+_c$ → pK$^0_S$η) = (4.35 ± 0.10 ± 0.20 ± 0.22) × 10 -3 . The first and second uncertainties are statistical and systematic, respectively, while the third ones arise from the uncertainty on $\mathscr{B}$(Λ$^+_c$ → pK$^0_S$). The mode Λ$^+_c$ → pK$^0_S$K$^0_S$ is observed for the first time and has a statistical significance of >10σ. The branching fraction of Λ$^+_c$ → pK$^0_S$η has been measured with a threefold improvement in precision over previous results and is found to be consistent with the world average.
79 ASTRONOMY AND ASTROPHYSICS↗
Isoreticular Tolerance and Phase Selection in the Synthesis of Multi‐Module Metal–Organic Frameworks for Gas Separation and Electrocatalytic OER
Abstract Although metal–organic frameworks are coordination‐driven assemblies, the structural prediction and design using metal‐ligand interactions can be unreliable due to other competing interactions. Leveraging non‐coordination interactions to develop porous assemblies could enable new materials and applications. Here, we use a multi‐module MOF system to explore important and pervasive impact of ligand‐ligand interactions on metal‐ligand as well as ligand‐ligand co‐assembly process. It is found that ligand‐ligand interactions play critical roles on the scope or breakdown of isoreticular chemistry. With cooperative di‐ and tri‐topic ligands, a family of Ni‐MOFs has been synthesized in various structure types including partitioned MIL‐88‐acs ( pacs ), interrupted pacs (i‐ pacs ), and UMCM‐1‐muo. A new type of isoreticular chemistry on the muo platform is established between two drastically different chemical systems. The gas sorption and electrocatalytic studies were performed that reveal excellent performance such as high C 2 H 2 /CO 2 selectivity of 21.8 and high C 2 H 2 uptake capacity of 114.5 cm 3 /g at 298 K and 1 bar.
Xiao, Yuchen [Department of Chemistry University o↗
Isoreticular Tolerance and Phase Selection in the Synthesis of Multi‐Module Metal–Organic Frameworks for Gas Separation and Electrocatalytic OER
Abstract Although metal–organic frameworks are coordination‐driven assemblies, the structural prediction and design using metal‐ligand interactions can be unreliable due to other competing interactions. Leveraging non‐coordination interactions to develop porous assemblies could enable new materials and applications. Here, we use a multi‐module MOF system to explore important and pervasive impact of ligand‐ligand interactions on metal‐ligand as well as ligand‐ligand co‐assembly process. It is found that ligand‐ligand interactions play critical roles on the scope or breakdown of isoreticular chemistry. With cooperative di‐ and tri‐topic ligands, a family of Ni‐MOFs has been synthesized in various structure types including partitioned MIL‐88‐acs ( pacs ), interrupted pacs (i‐ pacs ), and UMCM‐1‐muo. A new type of isoreticular chemistry on the muo platform is established between two drastically different chemical systems. The gas sorption and electrocatalytic studies were performed that reveal excellent performance such as high C 2 H 2 /CO 2 selectivity of 21.8 and high C 2 H 2 uptake capacity of 114.5 cm 3 /g at 298 K and 1 bar.
Xiao, Yuchen [Department of Chemistry University o↗
Understanding the origin of structure sensitivity in hydrodechlorination of trichloroethylene on a palladium catalyst
Periodic density functional theory (DFT) calculations are employed to understand the origin of structure sensitivity in hydrodechlorination (HDC) of trichloroethylene (TCE) over different facets of a palladium catalyst. The HDC reaction is simulated on the terrace (Pd (111) and Pd (100)) and undercoordinated (Pd (211) and Pd (110)) sites of the Pd catalyst. The most stable binding configuration of TCE on the Pd surfaces is observed to be through the di-σ mode of binding, wherein each carbon atom of the TCE molecule is adsorbed atop of the Pd atom. On comparing TCE adsorption over different facets of Pd, a maximum binding energy of –178 kJ mol –1 is calculated over the Pd (110) surface. TCE, upon adsorption on Pd catalyst, undergoes dechlorination followed by hydrogenation of the hydrocarbon intermediates. The activation energies for C–Cl bond dissociation steps are significantly low when compared to the hydrogenation steps. The chlorine released from dechlorination tends to block the active sites, thereby poisoning the surface with high binding energies (B.E > –160 kJ mol –1 ) on all the surfaces. The trend in chlorine binding energies on Pd facets follows: Pd (110) > Pd (211) > Pd (100) > Pd (111). The removal of surface chlorine is facilitated by its reaction with surface hydrogen to form hydrogen chloride. The activation energy for hydrogen chloride formation is calculated to be 90 kJ mol –1 and 88 kJ mol –1 on Pd (111) and Pd (100) terrace sites, respectively and 109 kJ mol –1 and 118 kJ mol –1 on the step Pd (211) and corrugated Pd (110) facets, respectively. This suggests the ease of removal of Cl as HCl from the terrace sites as compared to the step and corrugated sites. The structure sensitivity in the TCE HDC reaction could possibly arise due to the differences in the energetics of Cl removal on different Pd facets. As a result, this mechanistic understanding could provide a rationale for designing suitable catalysts for the HDC of TCE.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Frequentist cosmological constraints from full-shape clustering measurements in DESI DR1
We present a frequentist analysis of clustering measurements from Data Release 1 of the Dark Energy Spectroscopic Instrument (DESI) using the standard profile likelihood method. While Bayesian inferences for effective field theory models of galaxy clustering can be highly sensitive to prior choices for extended cosmological models, frequentist inferences are not susceptible to such effects. We compare frequentist and Bayesian constraints for the parameter set {σ 8 , H 0 , Ω m , w 0 , w a } using the full-shape power spectrum multipoles, post-reconstruction baryon acoustic oscillation (BAO) measurements, and external datasets from the CMB and type Ia supernovae measurements. The frequentist confidence intervals are significantly shifted relative to the Bayesian credible intervals for the w 0 w a CDM model, unless supernovae data are included. When DESI full-shape and BAO data are fit jointly, we obtain the following 1σ frequentist confidence intervals for ΛCDM (w 0 w a CDM): σ 8 = 0.863 +0.048 -0.040 , H 0 = 68.96 +0.81 -0.80 km s -1 Mpc -1 , Ω m = 0.3034 ± 0.0110 (σ 8 = 0.782 +0.060 -0.036 , H 0 = 63.7 +4.2 -2.0 km s -1 Mpc -1 , Ω m = 0.378 +0.024 -0.047 , w 0 = -0.16 +0.10 -0.50 , w a = -3.0 +1.7 ), corresponding to 0.8σ, 0.3σ, 0.7σ (2.1σ, 4.1σ, 6.5σ, 6.3σ, 6.6σ) shifts between the maximum likelihood estimate and the Bayesian posterior mean for ΛCDM (w 0 w a CDM) respectively.
Bayesian reasoning↗
Measurement of Beam-Correlated Background Neutrons from the Fermilab Booster Neutrino Beam in ANNIE Phase-I
The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) aims to make a unique measurement of neutron yield from neutrino-nucleus interactions and to perform R&D for the next generation of water-based neutrino detectors. In this paper, we characterize beam-induced neutron backgrounds in the experimental hall at Fermi National Accelerator Laboratory. It is shown that the background levels are sufficiently low to allow the next stage of the experiment to proceed. These measurements are relevant to other Booster Neutrino Beam (BNB) [1] experiments located adjacent to ANNIE Hall, where dirt neutrons and sky-shine could present similar backgrounds.
Particle identification methods↗
Spectroscopic Characterization of redMaPPer Galaxy Clusters with DESI
Optical galaxy cluster identification algorithms such as redMaPPer promise to enable an array of astrophysical and cosmological studies, but suffer from biases whereby galaxies in front of and behind a galaxy cluster are mistakenly associated with the primary cluster halo. These projection effects caused by irreducible photometric redshift uncertainty must be quantified to facilitate the use of optical cluster catalogues. We present measurements of galaxy cluster projection effects and velocity dispersion using spectroscopy from the Dark Energy Spectroscopic Instrument. Our findings are as follows: we confirm that the fraction of redMaPPer putative member galaxies mistakenly associated with cluster haloes is richness dependent, being more than twice as large at low richness than high richness; we present the first spectroscopic evidence of an increase in projection effects with increasing redshift, by as much as 25 per cent from $z\sim 0.1$ to $z\sim 0.2$; moreover, we find qualitative evidence for luminosity dependence in projection effects, with fainter galaxies being more commonly far behind clusters than their bright counterparts; finally, we fit the scaling relation between measured mean spectroscopic richness and velocity dispersion, finding an implied linear scaling between spectroscopic richness and halo mass. We discuss further directions for the application of spectroscopic data sets to improve use of optically selected clusters to test cosmological models.
clusters↗
Study of deeply virtual Compton scattering at the future electron-ion collider
This study presents the impact of future measurements of deeply virtual Compton scattering (DVCS) with the ePIC detector at the electron-ion collider (EIC), currently under construction at Brookhaven National Laboratory. The considered process is sensitive to generalized parton distributions (GPDs), the understanding of which is a cornerstone of the EIC physics program. Our study marks a milestone in the preparation of DVCS measurements at EIC and provides a reference point for future analyses. In addition to presenting distributions of basic kinematic variables obtained with the latest ePIC design and simulation software, we examine the impact of future measurements on the understanding of nucleon tomography and DVCS Compton form factors, which are directly linked to GPDs. We also assess the impact of radiative corrections and background contribution arising from exclusive π 0 production.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Measurement of the branching fraction of Ξ c 0 → Λ c + π - at Belle
Based on a data sample of 983 fb -1 collected with the Belle detector at the KEKB asymmetric-energy e + e - collider, we present the study of the heavy-flavor-conserving decay Ξ$^{0}_{c}$ → Λ$^{+}_{c}$π - with Λ$^{+}_{c}$ reconstructed via its pK - π + decay mode. The branching fraction ratio $\mathscr{B}$(Ξ$^{0}_{c}$ → Λ$^{+}_{c}$π - )/$\mathscr{B}$(Ξ$^{0}_{c}$ → Ξ - π + ) is measured to be 0.38 ±0.04 ±0.04. Combining with the world average value of $\mathscr{B}$(Ξ$^{0}_{c}$ → Ξ - π + ), the branching fraction $\mathscr{B}$(Ξ$^{0}_{c}$ → Λ$^{+}_{c}$π - ) is deduced to be (0.54 ±0.05 ±0.05 ±0.12)%. Here, the uncertainties above are statistical, systematic, and from $\mathscr{B}$(Ξ$^{0}_{c}$ → Ξ - π + ), respectively.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
First observation of B → $\bar{D}$ 1 (→ $\bar{D}$ π + π - ) $\ell$ + ν $\ell$ and measurement of the B → $\bar{D}$ (*) π$\ell$ + ν $\ell$ and B → $\bar{D}$ (*) π + π - $\ell$+ ν $\ell$ branching fractions with hadronic tagging at Belle
We report measurements of the ratios of branching fractions for B → $\bar{D}$(*) π$\ell$+ v $\ell$ and B → $\bar{D}$(*)π + π - $\ell$ + v $\ell$ relative to B → $\bar{D}$*$\ell$ + v $\ell$ decays with $\ell$ = e, μ. These results are obtained from a data sample that contains 772 × 10 6 $B\bar{B}$ pairs collected near the $\Upsilon$(4S) resonance with the Belle detector at the KEKB asymmetric energy e + e - collider.
79 ASTRONOMY AND ASTROPHYSICS↗
Measurement of beam-correlated background neutrons from the Fermilab Booster Neutrino Beam in ANNIE Phase-I (Final Technical Report)
The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) aims to make a unique measurement of neutron yield from neutrino-nucleus interactions and to perform R&D for the next generation of water-based neutrino detectors. In this paper, we characterize beam-induced neutron backgrounds in the experimental hall at Fermi National Accelerator Laboratory. It is shown that the background levels are sufficiently low to allow the next stage of the experiment to proceed. These measurements are relevant to other Booster Neutrino Beam (BNB) experiments located adjacent to ANNIE Hall, where dirt neutrons and sky-shine could present similar backgrounds.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗