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1. Search for supersymmetry in final states with missing transverse momentum and three or more b-jets in 139 fb$$^{-1}$$ of proton–proton collisions at $$\sqrt{s} = 13$$ TeV with the ATLAS detector

   https://doi.org/10.1140/epjc/s10052-023-11543-6  

   Aad, G. ; Abbott, B. ; Abbott, D. C. ; Abeling, K. ; Abidi, S. H. ; Aboulhorma, A. ; Abramowicz, H. ; Abreu, H. ; Abulaiti, Y. ; Abusleme Hoffman, A. C. ; et al ( July 2023 , The European Physical Journal C)

   A search for supersymmetry involving the pair production of gluinos decaying via off-shell third-generation squarks into the lightest neutralino$$(\tilde{\chi }^0_1)$$$\left({\tilde{\chi }}_1^0\right)$is reported. It exploits LHC proton–proton collision data at a centre-of-mass energy$$\sqrt{s} = 13$$$\sqrt{s}=13$TeV with an integrated luminosity of 139 fb$$^{-1}$$${}^{-1}$collected with the ATLAS detector from 2015 to 2018. The search uses events containing large missing transverse momentum, up to one electron or muon, and several energetic jets, at least three of which must be identified as containingb-hadrons. Both a simple kinematic event selection and an event selection based upon a deep neural-network are used. No significant excess above the predicted background is found. In simplified models involving the pair production of gluinos that decay via off-shell top (bottom) squarks, gluino masses less than 2.44 TeV (2.35 TeV) are excluded at 95% CL for a massless$$\tilde{\chi }^0_1.$$${\tilde{\chi }}_1^0.$Limits are also set on the gluino mass in models with variable branching ratios for gluino decays to$$b\bar{b}\tilde{\chi }^0_1,$$$b\overline{b}{\tilde{\chi }}_1^0,$$$t\bar{t}\tilde{\chi }^0_1$$$t\overline{t}{\tilde{\chi }}_1^0$and$$t\bar{b}\tilde{\chi }^-_1/\bar{t}b\tilde{\chi }^+_1.$$$t\overline{b}{\tilde{\chi }}_1^{-}/\overline{t}b{\tilde{\chi }}_1^{+}.$

    

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2. Hint of a new scalar interaction in LHCb data?

   https://doi.org/10.1140/epjc/s10052-024-12890-8  

   Datta, Alakabha ; Marfatia, Danny ; Mukherjee, Lopamudra ( June 2024 , The European Physical Journal C)

   We explain recent LHCb measurements of the lepton universality ratios,$$R_{D^{(*)}}^{\tau /\ell }\equiv \frac{\mathcal {B}(\bar{B} \rightarrow D^{(*)+} \tau ^- \bar{\nu }_\tau )}{\mathcal {B}(\bar{B} \rightarrow D^{(*)+}\ell ^- \bar{\nu }_\ell )}$$$R_{D^{(\ast )}}^{\tau /\ell }\equiv \frac{B(\overline{B}\to D^{(\ast )+}{\tau }^{-}{\overline{\nu }}_{\tau })}{B(\overline{B}\to D^{(\ast )+}{\ell }^{-}{\overline{\nu }}_{\ell })}$and$${R(\Lambda _c^+)}^{\tau /\ell } \equiv \frac{\mathcal {B}(\Lambda _b \rightarrow \Lambda _c^+ \tau ^- \bar{\nu }_{\tau })}{\mathcal {B}(\Lambda _b \rightarrow \Lambda _c^+ \ell ^- \bar{\nu }_{\ell })}$$${R\left({\Lambda }_c^{+}\right)}^{\tau /\ell }\equiv \frac{B({\Lambda }_b\to {\Lambda }_c^{+}{\tau }^{-}{\overline{\nu }}_{\tau })}{B({\Lambda }_b\to {\Lambda }_c^{+}{\ell }^{-}{\overline{\nu }}_{\ell })}$with$$\ell =\mu $$$\ell =\mu$, via new physics that affects$$R_D^{\tau /\ell }$$$R_D^{\tau /\ell }$and$$R(\Lambda _c^+)^{\tau /\ell }$$$R{\left({\Lambda }_c^{+}\right)}^{\tau /\ell }$but not$$R_{D^*}^{\tau /\ell }$$$R_{D^{\ast }}^{\tau /\ell }$. The scalar operator in the effective theory for new physics is indicated. We find that the forward-backward asymmetry and$$\tau $$$\tau$polarization in$$\bar{B} \rightarrow D^+ \tau ^{-} \bar{\nu }_{\tau }$$$\overline{B}\to D^{+}{\tau }^{-}{\overline{\nu }}_{\tau }$and$$\Lambda _b \rightarrow \Lambda _c^+ \tau ^- \bar{\nu }_{\tau }$$${\Lambda }_b\to {\Lambda }_c^{+}{\tau }^{-}{\overline{\nu }}_{\tau }$decays are significantly affected by the scalar interaction. We construct a simple two Higgs doublet model as a realization of our scenario and consider lepton universality in semileptonic charm and top decays, radiativeBdecay,B-mixing, and$$Z \rightarrow b \bar{b}$$$Z\to b\overline{b}$.

    

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3. Search for prompt production of pentaquarks in charm hadron final states

   https://doi.org/10.1103/PhysRevD.110.032001  

   Aaij, R ; Abdelmotteleb, A_S W ; Abellan_Beteta, C ; Abudinén, F ; Ackernley, T ; Adeva, B ; Adinolfi, M ; Adlarson, P ; Afsharnia, H ; Agapopoulou, C ; et al ( August 2024 , Physical Review D)

   A search for hidden-charm pentaquark states decaying to a range of${\mathrm{\Sigma }}_c\overline{D}$and${\mathrm{\Lambda }}_c^{+}\overline{D}$final states, as well as doubly charmed pentaquark states to${\mathrm{\Sigma }}_{c}D$and${\mathrm{\Lambda }}_c^{+}D$, is made using samples of proton-proton collision data corresponding to an integrated luminosity of$5.7{\mathrm{fb}}^{-1}$recorded by the LHCb detector at$\sqrt{s}=13\mathrm{TeV}$. Since no significant signals are found, upper limits are set on the pentaquark yields relative to that of the${\mathrm{\Lambda }}_c^{+}$baryon in the${\mathrm{\Lambda }}_c^{+}\to p{K}^{-}{\pi }^{+}$decay mode. The known pentaquark states are also investigated, and their signal yields are found to be consistent with zero in all cases.

   © 2024 CERN, for the LHCb Collaboration2024CERN 

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4. Safety First: Stability and Dissipation of Line-tied Force-free Flux Tubes in Magnetized Coronae

   https://doi.org/10.3847/1538-4357/ad3206  

   Rugg, N. ; Mahlmann, J. F. ; Spitkovsky, A. ( May 2024 , The Astrophysical Journal)

   Magnetized plasma columns and extended magnetic structures with both footpoints anchored to a surface layer are an important building block of astrophysical dissipation models. Current loops shining in X-rays during the growth of plasma instabilities are observed in the corona of the Sun and are expected to exist in highly magnetized neutron star magnetospheres and accretion disk coronae. For varying twist and system sizes, we investigate the stability of line-tied force-free flux tubes and the dissipation of twist energy during instabilities using linear analysis and time-dependent force-free electrodynamics simulations. Kink modes (m= 1) and efficient magnetic energy dissipation develop for plasma safety factorsq≲ 1, whereqis the inverse of the number of magnetic field line windings per column length. Higher-order fluting modes (m> 1) can distort equilibrium flux tubes forq> 1 but induce significantly less dissipation. In our analysis, the characteristic pitch${\tilde{\mu }}_0$of flux-tube field lines determines the growth rate ($\propto {\tilde{\mu }}_0^3$) and minimum wavelength of the kink instability ($\propto {\tilde{\mu }}_0^{-1}$). We use these scalings to determine a minimum flux tube length for the growth of the kink instability for any given${\tilde{\mu }}_0$. By drawing analogies to idealized magnetar magnetospheres with varying regimes of boundary shearing rates, we discuss the expected impact of the pitch-dependent growth rates for magnetospheric dissipation in magnetar conditions.

    

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5. Measurement of CP asymmetries in B0→KS0KS0KS0 decays at Belle II

   https://doi.org/10.1103/PhysRevD.109.112020  

   Adachi, I ; Aggarwal, L ; Ahmed, H ; Aihara, H ; Akopov, N ; Aloisio, A ; Anh_Ky, N ; Asner, D M ; Atmacan, H ; Aushev, T ; et al ( June 2024 , Physical Review D)

   We report a measurement of decay-time-dependent charge-parity ($CP$) asymmetries in$B^0\to K_S^0{K}_S^0{K}_S^0$decays. We use$387\times {10}^6$$B\overline{B}$pairs collected at the$\mathrm{\Upsilon }(4S)$resonance with the Belle II detector at the SuperKEKB asymmetric-energy electron-positron collider. We reconstruct 220 signal events and extract the$CP$-violating parameters$S$and$C$from a fit to the distribution of the decay-time difference between the two$B$mesons. The resulting confidence region is consistent with previous measurements in$B^0\to K_S^0{K}_S^0{K}_S^0$and$B^0\to (c\overline{c})K^0$decays and with predictions based on the standard model.

   Published by the American Physical Society2024 

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