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1. First measurement of $D_{s1}\left(1^{+}\right)(2536{)}^{+}$ and $D_{s2}^{*}\left(2^{+}\right)(2573{)}^{+}$ production in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ at the LHC

   https://doi.org/10.1103/PhysRevD.111.112005  

   Acharya, S; Agarwal, A; Aglieri_Rinella, G; Aglietta, L; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Ahuja, I; et al (June 2025, Physical Review D)

   The production yields of the orbitally excited charm-strange mesons ${\mathrm{D}}_{\mathrm{s}1}\left(1^{+}\right)(2536{)}^{+}$ and ${\mathrm{D}}_{\mathrm{s}2}^{*}\left(2^{+}\right)(2573{)}^{+}$ were measured for the first time in proton-proton (pp) collisions at a center-of-mass energy of $\sqrt{s}=13\mathrm{TeV}$ with the ALICE experiment at the LHC. The ${\mathrm{D}}_{\mathrm{s}1}^{+}$ and ${\mathrm{D}}_{\mathrm{s}2}^{*+}$ mesons were measured at midrapidity ( $\left|y\right|<0.5$ ) in minimum-bias and high-multiplicity pp collisions in the transverse-momentum interval $2<p_{\mathrm{T}}<24\mathrm{GeV}/c$ . Their production yields relative to the ${\mathrm{D}}_{\mathrm{s}}^{+}$ ground-state yield were found to be compatible between minimum-bias and high-multiplicity collisions, as well as with previous measurements in ${\mathrm{e}}^{\pm }\mathrm{p}$ and ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions. The measured ${\mathrm{D}}_{\mathrm{s}1}^{+}/{\mathrm{D}}_{\mathrm{s}}^{+}$ and ${\mathrm{D}}_{\mathrm{s}2}^{*+}/{\mathrm{D}}_{\mathrm{s}}^{+}$ yield ratios are described by statistical hadronization models and can be used to tune the parameters governing the production of excited charm-strange hadrons in Monte Carlo generators, such as 8. 

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2. $D^0$ -meson-tagged jet axes difference in proton-proton collisions at $\sqrt{s}=5.02\mathrm{TeV}$

   https://doi.org/10.1103/nt4q-7t77  

   Acharya, S; Agarwal, A; Aglieri_Rinella, G; Aglietta, L; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Ahuja, I; et al (November 2025, Physical Review D)

   Heavy-flavor quarks produced in proton-proton (pp) collisions provide a unique opportunity to investigate the evolution of quark-initiated parton showers from initial hard scatterings to final-state hadrons. By examining jets that contain heavy-flavor hadrons, this study explores the effects of both perturbative and nonperturbative QCD on jet formation and structure. The angular differences between various jet axes, $\mathrm{\Delta }{R}_{\mathrm{axis}}$ , offer insight into the radiation patterns and fragmentation of charm quarks. The first measurement of $D^0$ -tagged jet axes differences in pp collisions at $\sqrt{s}=5.02\mathrm{TeV}$ by the ALICE experiment at the LHC is presented for jets with transverse momentum $p_{\mathrm{T}}^{\text{ch jet}}\ge 10\mathrm{GeV}/c$ and $D^0$ mesons with $p_{\mathrm{T}}^{{\mathrm{D}}^0}\ge 5\mathrm{GeV}/c$ . In this $D^0$ -meson-tagged jet measurement, three jet axis definitions, each with different sensitivities to soft, wide-angle radiation, are used: the standard axis, soft drop groomed axis, and winner-takes-all axis. Measurements of the radial distributions of $D^0$ mesons with respect to the jet axes, $\mathrm{\Delta }{R}_{\mathrm{axis}\text{−}{\mathrm{D}}^0}$ , are reported, along with the angle, $\mathrm{\Delta }{R}_{\mathrm{axis}}$ , between the three jet axes. The $D^0$ meson emerges as the leading particle in these jets, closely aligning with the winner-takes-all axis and diverging from the standard jet axis. The results also examine how varying the sensitivity to soft radiation with grooming influences the orientation of the soft drop jet axis and uncover that charm-jet structure is more likely to survive grooming when the soft drop axis is further from the $D^0$ direction, providing further evidence of the dead-cone effect recently measured by ALICE. 

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3. Fully plasma-based electron injector for a linear collider or XFEL

   https://doi.org/10.1103/PhysRevResearch.7.023118  

   Dalichaouch, T N; Xu, X L; Li, F; Tsung, F S; Mori, W B (May 2025, Physical Review Research)

   We demonstrate through high-fidelity particle-in-cell (PIC) simulations a simple approach for efficiently generating $20+$ GeV electron beams with the necessary charge, energy spread, and emittance for use as an injector in a future linear collider or a next generation XFEL. A high quality injected bunch is generated by self-focusing an unmatched electron driver in a nonlinear plasma wakefield. Over pump depletion distances, the drive beam dynamics and self-loading effects lead to high energy, low-energy spread output beams. For plasma densities of ${10}^{18}\mathrm{c}{\mathrm{m}}^{-3}$ , PIC simulation results indicate that self-injected beams with $0.52\mathrm{n}\mathrm{C}$ charge can be accelerated to 20 GeV with projected core energy spreads of $\lesssim 1\%$ , normalized slice emittances of $110\mathrm{n}\mathrm{m}$ , peak normalized brightness of $\gtrsim {10}^{19}\mathrm{A}/{\mathrm{m}}^2/{\mathrm{rad}}^2$ , and transfer efficiencies of $\gtrsim 44\%$ . 

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4. Magneto-optical trap of titanium atoms

   https://doi.org/10.1103/PhysRevResearch.7.023025  

   Eustice, Scott; Schrott, Jackson; Stöltzel, Anke; Wolf, Julian; Novoa, Diego; Cassella, Kayleigh; Stamper-Kurn, Dan M (April 2025, Physical Review Research)

   We realize a magneto-optical trap (MOT) of titanium (Ti) atoms, performing laser cooling on the 498 nm transition between the long-lived $3{\mathrm{d}}^3\left({}^4\mathrm{F}\right)4\mathrm{s}{\mathrm{a}}^5{\mathrm{F}}_5$ metastable state and the $3{\mathrm{d}}^3\left({}^4\mathrm{F}\right)4\mathrm{p}{\mathrm{y}}^5{\mathrm{G}}_6^{\mathrm{o}}$ excited state. Without the addition of any repumping light, we observe MOTs of the three stable, $I=0$ bosonic isotopes, ${}^{46}\mathrm{Ti}, {}^{48}\mathrm{Ti}$ , and ${}^{50}\mathrm{Ti}$ . Up to $8.30\left(26\right)\times {10}^5{}^{48}\mathrm{Ti}$ atoms are trapped at a maximum density of $1.3\left(4\right)\times {10}^{11}{\mathrm{cm}}^{-3}$ and at a temperature of $90\left(15\right)\mu \mathrm{K}$ . By measuring the decay of the MOT, we constrain the leakage branching ratio of the cooling transition ( $\le 2.5\times {10}^{-6}$ ) and the two-body loss coefficient ( $\le 2\times {10}^{-10}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ ). Our approach to laser cooling Ti can be applied to other transition metals, enabling a significant expansion of the elements that can be laser cooled. Published by the American Physical Society2025 

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5. Search for charmed baryons in the ${\mathrm{\Lambda }}_c^{+}\eta$ system and measurement of the branching fractions of ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and ${\mathrm{\Lambda }}_c(2940{)}^{+}$ decaying to ${\mathrm{\Lambda }}_c^{+}\eta$ and $p{D}^0$ relative to ${\mathrm{\Sigma }}_c\left(2455\right)\pi$

   https://doi.org/10.1103/PhysRevD.110.032021  

   Li, S X; Shen, C P; Adachi, I; Ahn, J K; Aihara, H; Asner, D M; Atmacan, H; Aushev, T; Ayad, R; Banerjee, Sw; et al (August 2024, Physical Review D)

   We search for excited charmed baryons in the ${\mathrm{\Lambda }}_c^{+}\eta$ system using a data sample corresponding to an integrated luminosity of $980{\mathrm{fb}}^{-1}$ . The data were collected by the Belle detector at the KEKB $e^{+}{e}^{-}$ asymmetric-energy collider. No significant signals are found in the ${\mathrm{\Lambda }}_c^{+}\eta$ mass spectrum, including the known ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and ${\mathrm{\Lambda }}_c(2940{)}^{+}$ . Clear ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and ${\mathrm{\Lambda }}_c(2940{)}^{+}$ signals are observed in the $p{D}^0$ mass spectrum. We set upper limits at 90% credibility level on ratios of branching fractions of ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and ${\mathrm{\Lambda }}_c(2940{)}^{+}$ decaying to ${\mathrm{\Lambda }}_c^{+}\eta$ relative to ${\mathrm{\Sigma }}_c\left(2455\right)\pi$ of $<0.13$ for the ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and $<1.11$ for the ${\mathrm{\Lambda }}_c(2940{)}^{+}$ . We measure ratios of branching fractions of ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and ${\mathrm{\Lambda }}_c(2940{)}^{+}$ decaying to $p{D}^0$ relative to ${\mathrm{\Sigma }}_c\left(2455\right)\pi$ of $0.75\pm 0.03\left(\mathrm{stat}\right)\pm 0.07\left(\mathrm{syst}\right)$ for the ${\mathrm{\Lambda }}_c(2880{)}^{+}$ and $3.59\pm 0.21\left(\mathrm{stat}\right)\pm 0.56\left(\mathrm{syst}\right)$ for the ${\mathrm{\Lambda }}_c(2940{)}^{+}$ . Published by the American Physical Society2024 

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