Showing papers by "A. Passeri published in 2022"

Precision tests of quantum mechanics and $$ \mathcal{CPT} $$ symmetry with entangled neutral kaons at KLOE

Abstract: A bstract The quantum interference between the decays of entangled neutral kaons is studied in the process ϕ → K S K L → π + π − π + π − , which exhibits the characteristic Einstein-Podolsky-Rosen correlations that prevent both kaons to decay into π + π − at the same time. This constitutes a very powerful tool for testing at the utmost precision the quantum coherence of the entangled kaon pair state, and to search for tiny decoherence and $$ \mathcal{CPT} $$ CPT violation effects, which may be justified in a quantum gravity framework. The analysed data sample was collected with the KLOE detector at DAΦNE, the Frascati ϕ -factory, and corresponds to an integrated luminosity of about 1.7 fb − 1 , i.e. to about 1 . 7 × 10 9 ϕ → K S K L decays produced. From the fit of the observed ∆ t distribution, being ∆ t the difference of the kaon decay times, the decoherence and $$ \mathcal{CPT} $$ CPT violation parameters of various phenomenological models are measured with a largely improved accuracy with respect to previous analyses. The results are consistent with no deviation from quantum mechanics and $$ \mathcal{CPT} $$ CPT symmetry, while for some parameters the precision reaches the interesting level at which — in the most optimistic scenarios — quantum gravity effects might show up. They provide the most stringent limits up to date on the considered models.

Search for a Dark Photon and an Invisible Dark Higgs Boson in μ^{+}μ^{-} and Missing Energy Final States with the Belle II Experiment.

Abstract: The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A^{'} and h^{'} in the dark Higgsstrahlung process e^{+}e^{-}→A^{'}h^{'} with A^{'}→μ^{+}μ^{-} and h^{'} invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34 fb^{-1}, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7-5.0 fb on the cross section and in the range of 1.7×10^{-8}-200×10^{-8} on the effective coupling ϵ^{2}×α_{D} for the A^{'} mass in the range of 4.0 GeV/c^{2}

Search for the decay B 0 s → η ′ K 0 S

Abstract: T. Pang,74 V. Savinov,74 I. Adachi,21, 17 H. Aihara,90 D. M. Asner,3 H. Atmacan,8 V. Aulchenko,4, 70 T. Aushev,23 R. Ayad,84 V. Babu,9 P. Behera,29 K. Belous,33 M. Bessner,20 V. Bhardwaj,26 B. Bhuyan,27 T. Bilka,5 A. Bobrov,4, 70 D. Bodrov,23, 48 G. Bonvicini,94 J. Borah,27 A. Bozek,66 M. Bračko,54, 39 P. Branchini,35 T. E. Browder,20 A. Budano,35 M. Campajola,34, 62 D. Červenkov,5 P. Chang,65 A. Chen,64 B. G. Cheon,19 K. Chilikin,48 H. E. Cho,19 K. Cho,43 S.-J. Cho,96 S.-K. Choi,7 Y. Choi,82 S. Choudhury,37 D. Cinabro,94 S. Cunliffe,9 S. Das,53 G. De Pietro,35 R. Dhamija,28 F. Di Capua,34, 62 J. Dingfelder,2 Z. Doležal,5 T. V. Dong,11 D. Dossett,56 S. Dubey,20 D. Epifanov,4, 70 T. Ferber,9 A. Frey,16 B. G. Fulsom,72 R. Garg,73 V. Gaur,93 N. Gabyshev,4, 70 A. Giri,28 P. Goldenzweig,40 E. Graziani,35 T. Gu,74 K. Gudkova,4, 70 C. Hadjivasiliou,72 S. Halder,85 K. Hayasaka,68 H. Hayashii,63 M. T. Hedges,20 C.-L. Hsu,83 T. Iijima,61, 60 K. Inami,60 G. Inguglia,32 A. Ishikawa,21, 17 R. Itoh,21, 17 M. Iwasaki,71 Y. Iwasaki,21 W. W. Jacobs,30 E.-J. Jang,18 S. Jia,13 Y. Jin,90 K. K. Joo,6 J. Kahn,40 D. Kalita,27 A. B. Kaliyar,85 K. H. Kang,41 G. Karyan,9 T. Kawasaki,42 C. Kiesling,55 C. H. Kim,19 D. Y. Kim,81 K.-H. Kim,96 Y.-K. Kim,96 K. Kinoshita,8 P. Kodyš,5 T. Konno,42 A. Korobov,4, 70 S. Korpar,54, 39 E. Kovalenko,4, 70 P. Križan,50, 39 R. Kroeger,57 P. Krokovny,4, 70 T. Kuhr,51 R. Kumar,75 K. Kumara,94 A. Kuzmin,4, 70, 48 Y.-J. Kwon,96 Y.-T. Lai,41 T. Lam,93 J. S. Lange,14 S. C. Lee,46 C. H. Li,49 J. Li,46 L. K. Li,8 Y. Li,13 L. Li Gioi,55 J. Libby,29 K. Lieret,51 D. Liventsev,94, 21 A. Martini,97 M. Masuda,89, 76 T. Matsuda,58 D. Matvienko,4, 70, 48 F. Meier,10 M. Merola,34, 62 F. Metzner,40 K. Miyabayashi,63 R. Mizuk,48, 23 G. B. Mohanty,85 R. Mussa,36 M. Nakao,21, 17 Z. Natkaniec,66 A. Natochii,20 L. Nayak,28 M. Niiyama,45 N. K. Nisar,3 S. Nishida,21, 17 K. Ogawa,68 S. Ogawa,87 H. Ono,67, 68 P. Oskin,48 P. Pakhlov,48, 59 G. Pakhlova,23, 48 S. Pardi,34 H. Park,46 S.-H. Park,21 A. Passeri,35 S. Patra,26 S. Paul,86, 55 T. K. Pedlar,52 R. Pestotnik,39 L. E. Piilonen,93 T. Podobnik,50, 39 V. Popov,23 E. Prencipe,24 M. T. Prim,2 A. Rostomyan,9 N. Rout,29 G. Russo,62 D. Sahoo,37 S. Sandilya,28 A. Sangal,8 L. Santelj,50, 39 T. Sanuki,88 G. Schnell,1, 25 Y. Seino,68 K. Senyo,95 M. E. Sevior,56 M. Shapkin,33 C. Sharma,53 C. P. Shen,13 J.-G. Shiu,65 F. Simon,55 J. B. Singh,73, ∗ A. Sokolov,33 E. Solovieva,48 S. Stanič,69 M. Starič,39 J. F. Strube,72 M. Sumihama,15, 76 T. Sumiyoshi,92 M. Takizawa,79, 22, 77 U. Tamponi,36 K. Tanida,38 N. Taniguchi,21 F. Tenchini,9 K. Trabelsi,47 M. Uchida,91 K. Uno,68 S. Uno,21, 17 P. Urquijo,56 R. Van Tonder,2 G. Varner,20 A. Vinokurova,4, 70 E. Waheed,21 E. Wang,74 M.-Z. Wang,65 X. L. Wang,13 M. Watanabe,68 S. Watanuki,96 E. Won,44 X. Xu,80 B. D. Yabsley,83 W. Yan,78 H. Ye,9 J. Yelton,12 J. H. Yin,44 C. Z. Yuan,31 Y. Zhai,37 Z. P. Zhang,78 V. Zhilich,4, 70 and V. Zhukova48

First Simultaneous K−p → (Σ/Λ)π Cross Sections Measurements at 98 MeV/c

Abstract: Kristian Piscicchia, Magdalena Skurzok∗,c,d, Michael Cargnelli, Raffaele Del Grande, Laura Fabbietti , Johann Marton, Pawel Moskal, Alessandro Scordo, Àngels Ramos, Diana Laura Sirghi, Oton Vazquez Doce, Johann Zmeskal, S lawomir Wycech , Paolo Branchini, Filippo Ceradini, Eryk Czerwiński, Erika De Lucia, Salvatore Fiore, Andrzej Kupsc , Giuseppe Mandaglio, Matteo Martini, Antonio Passeri, Vincenzo Patera, Elena Perez Del Rio, Andrea Selce, Micha l Silarski and Catalina Curceanu

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II.

Abstract: We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8 fb^{-1}, produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} and τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. We report 95% confidence-level upper limits on the branching-fraction ratio B(τ^{-}→e^{-}α)/B(τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ}) in the range (1.1-9.7)×10^{-3} and on B(τ^{-}→μ^{-}α)/B(τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}) in the range (0.7-12.2)×10^{-3} for α masses between 0 and 1.6 GeV/c^{2}. These results provide the most stringent bounds on invisible boson production from τ decays.

Measurements of the branching fraction, isospin asymmetry, and lepton-universality ratio in $B \to J/\psi K$ decays at Belle II

Abstract: We report a study of B → J/ψ ( (cid:96) + (cid:96) − ) K decays, where (cid:96) represents an electron or a muon, using e + e − collisions at the Υ(4 S ) resonance. The data were collected by the Belle II experiment at the SuperKEKB asymmetric-energy collider during 2019–2021, corresponding to an integrated luminosity of 189 fb − 1 . The measured quantities are the branching fractions ( B ) of the decay channels B + → J/ψ ( e + e − ) K + , B + → J/ψ ( µ + µ − ) K + , B 0 → J/ψ ( e + e − ) K 0 S , and B 0 → J/ψ ( µ + µ − ) K 0 S ; the lepton-flavor-dependent isospin asymmetries for the electron [ A I ( B → J/ψ ( e + e − ) K )] and muon [ A I ( B → J/ψ ( µ + µ − ) K )] channels; and the ratios of branching fractions between the muon and electron channels for the

Direct tests of T, CP, CPT symmetries in transitions of neutral K mesons with the KLOE experiment

Abstract: Tests of the T, CP and CPT symmetries in the neutral kaon system are 1 performed by the direct comparison of the probabilities of a kaon transition 2 process to its symmetry-conjugate. The exchange of in and out states re- 3 quired for a genuine test involving an anti-unitary transformation implied 4 by time-reversal is implemented exploiting the entanglement of K 0 K 0 pairs 5 produced at a φ -factory. 6 A data sample collected by the KLOE experiment at DAΦNE corresponding to an integrated luminosity of about 1.7 fb − 1 is analysed to study the ∆ t distributions of the φ → K S K L → π + π − π ± e ∓ ν and φ → K S K L → π ± e ∓ ν 3 π 0 processes, with ∆ t the difference of the kaon decay times. A comparison of the measured ∆ t distributions in the asymptotic region ∆ t (cid:29) τ S allows to test for the first time T and CPT symmetries in kaon transitions with a precision of few percent, and to observe CP violation with this novel method.

Large-Area SiPM Pixels (LASiPs) in SPECT

Abstract: A standard camera for Single Photon Emission Computed Tomography (SPECT) contains 50–100 photomultiplier tubes (PMTs) that occupy at least 50% of its volume. It is shielded by a thick layer of lead which makes it heavy and bulky. Replacing PMTs by silicon photomultipliers (SiPMs) could significantly reduce the weight and size of a SPECT camera. However, the main obstacle is the limited size of SiPMs: even with the largest commercially available SiPM of 6 × 6 mm2 a few thousand channels would be needed to fill a camera. As a solution, we propose to use Large Area SiPM Pixels (LASiPs) which are built by summing the currents of several SiPMs into a single output. We developed a LASiP prototype summing 8 SiPMs using the MUSIC ASIC. To test the feasibility of using this solution in SPECT, we built a proof-of-concept micro camera that consisted of four of our LASiP prototypes coupled to a 40 × 40 × 8 mm3 NaI(Tl) crystal. We were able to reconstruct simple images of a 99m Tc capillary with an intrinsic spatial resolution of ∼2 mm and an energy resolution of ∼11.6%. We also simulated the system with Geant4, finding a good agreement with our experimental results. The simulations were extended to a larger camera, aiming to study the impact of pixel size, shape and noise.

Study of the decay φ with the KLOE detector The KLOE Collaboration

Abstract: We measured, with the KLOE detector, the spectrum of π + π − invariant mass in a sample of 6 . 7 × 10 5 e + e − → π + π − γ events with the photon at large polar angle ( θ γ > 45 ◦ ) at a centre of mass energy √ s around the φ mass. We observe in this spectrum a clear contribution from the intermediate process φ → f 0 (980) γ . A sizeable effect is also observed in the distribution of the pion forward-backward asymmetry. We use different theoretical models to fit the spectrum and we determine the f 0 mass and coupling constants to the φ , to π + π − and to K ¯ K .

The Pendulum of Non-Alignment: Charting Myanmar's Great Power Diplomacy (2011–2021)

Abstract: Since independence, Myanmar has prioritised a non-aligned foreign policy to preserve autonomy in the international arena. Yet, it has done so in contrasting and sometimes opposite ways. Historically, Myanmar's great power diplomacy has resembled a pendulum swinging between two ideal types: ‘positive non-alignment’ and ‘negative neutralism’. The former represents a proactive blend of non-aligned behaviour that seeks to assert independence by achieving a diversified range of international partnerships, whereas the latter endeavours to accomplish the same goal through diplomatic disengagement and self-aloofness. This article analyses Myanmar's shifting recourse to opposite archetypes of alignment by examining its foreign policy between 2011 and 2021. Building upon a comprehensive theoretical classification of different forms of non-alignment, the analysis contends that Myanmar's evolving great power diplomacy is ultimately rooted in oscillating degrees of political legitimation held by its leaders, which pushed them to alternatively tilt towards positive non-alignment or negative neutralism.

Study of Exclusive B → πe + ν e Decays with Hadronic Full-event-interpretation Tagging in 189.3 fb − 1 of Belle II Data

Abstract: We present a reconstruction of the semileptonic decays B 0 → π − e + ν e and B + → π 0 e + ν e in a sample corresponding to 189.3 fb − 1 of Belle II data, using events where the partner B -meson is reconstructed from a large variety of hadronic channels via a tagging algorithm known as the full-event-interpretation. We determine the partial branching fractions in three bins of the squared momentum transfer to the leptonic system using fits to the distribution of the square of the missing mass. The partial branching fractions are summed to determine B ( B 0 → π − e + ν e ) = (1.43 ± 0.27(stat) ± 0.07(syst)) × 10 − 4 and B ( B + → π 0 e + ν e ) = (8.33 ±

First decay-time-dependent analysis of $B^{0} \to K_{S}^{0} \pi^{0}$ at Belle II

Abstract: We report measurements of the branching fraction ( B ) and direct CP -violating asymmetry ( A CP ) of the charmless decay B 0 → K 0 π 0 at Belle II. A sample of e + e − collisions, corresponding to 189 . 8 fb − 1 of integrated luminosity, recorded at the Υ (4 S ) resonance is used for the first decay-time-dependent analysis of these decays within the experiment. We reconstruct about 135 signal candidates, and measure B ( B 0 → K 0 π 0 ) = [11 . 0 ± 1 . 2(stat) ± 1 . 0(syst)] × 10 − 6 and A CP ( B 0 → K 0 π 0 ) = − 0 . 41 +0 . 30 − 0 . 32 (stat) ± 0 . 09(syst).

Study of B + → pnπ 0

Abstract: K.-N. Chu , Y.-R. Lin , M.-Z. Wang , I. Adachi , K. Adamczyk , H. Aihara , S. Al Said , D. M. Asner , H. Atmacan , V. Aulchenko , T. Aushev , R. Ayad , V. Babu , Sw. Banerjee , P. Behera , K. Belous , J. Bennett , M. Bessner , V. Bhardwaj , B. Bhuyan , T. Bilka , D. Biswas , D. Bodrov , G. Bonvicini , J. Borah , A. Bozek , M. Bračko , P. Branchini , T. E. Browder , A. Budano , M. Campajola , D. Červenkov , M.-C. Chang , P. Chang , A. Chen , B. G. Cheon , K. Chilikin , H. E. Cho , K. Cho , S.-J. Cho , S.-K. Choi , Y. Choi , S. Choudhury , D. Cinabro , G. De Nardo , G. De Pietro , R. Dhamija , F. Di Capua , J. Dingfelder , Z. Doležal , T. V. Dong , D. Epifanov , T. Ferber , D. Ferlewicz , B. G. Fulsom , V. Gaur , A. Garmash , A. Giri , P. Goldenzweig , B. Golob , E. Graziani , T. Gu , K. Gudkova , C. Hadjivasiliou , S. Halder , X. Han , K. Hayasaka , H. Hayashii , W.-S. Hou , C.-L. Hsu , K. Huang , T. Iijima , K. Inami , N. Ipsita , A. Ishikawa , R. Itoh , M. Iwasaki , W. W. Jacobs , E.-J. Jang , Y. Jin , K. K. Joo , D. Kalita , A. B. Kaliyar , T. Kawasaki , C. Kiesling , C. H. Kim , D. Y. Kim , K.-H. Kim , Y.-K. Kim , P. Kodyš , T. Konno , A. Korobov , S. Korpar , E. Kovalenko , P. Križan , P. Krokovny , T. Kuhr , R. Kumar , K. Kumara , A. Kuzmin , Y.-J. Kwon , Y.-T. Lai , T. Lam , J. S. Lange , S. C. Lee , C. H. Li , J. Li , L. K. Li , S. X. Li , Y. Li , Y. B. Li , L. Li Gioi , J. Libby , K. Lieret , D. Liventsev , T. Luo , M. Masuda , T. Matsuda , D. Matvienko , S. K. Maurya , F. Meier , M. Merola , F. Metzner , K. Miyabayashi , R. Mizuk , G. B. Mohanty , I. Nakamura , M. Nakao , Z. Natkaniec , A. Natochii , L. Nayak , N. K. Nisar , S. Nishida , Y. Onuki , P. Oskin , P. Pakhlov , G. Pakhlova , S. Pardi , H. Park , J. Park , A. Passeri , S. Paul , T. K. Pedlar , R. Pestotnik , L. E. Piilonen , T. Podobnik , E. Prencipe , M. T. Prim , A. Rostomyan , N. Rout , G. Russo , S. Sandilya , L. Santelj , V. Savinov , G. Schnell , C. Schwanda , Y. Seino , K. Senyo , M. E. Sevior , W. Shan , M. Shapkin , C. Sharma , C. P. Shen , J.-G. Shiu , B. Shwartz , F. Simon , A. Sokolov , E. Solovieva , M. Starič , Z. S. Stottler , J. F. Strube , M. Sumihama , K. Sumisawa , T. Sumiyoshi , M. Takizawa , U. Tamponi , K. Tanida , F. Tenchini , K. Trabelsi , M. Uchida , T. Uglov , Y. Unno , S. Uno , P. Urquijo , Y. Usov , S. E. Vahsen , R. van Tonder , G. Varner , K. E. Varvell , A. Vinokurova , A. Vossen , S. Watanuki , E. Won , X. Xu , B. D. Yabsley , W. Yan , S. B. Yang , J. Yelton , J. H. Yin , C. Z. Yuan , L. Yuan , Y. Yusa , Z. P. Zhang , V. Zhilich , and V. Zhukova (The Belle Collaboration)

A new $K_S \to \pi e \nu$ branching fraction measurement from KLOE-2

Abstract: A new measurement of the branching fraction for the decay $K_S \to \pi e u$ is presented, based on a sample of 300 million $K_S$ mesons recorded by the KLOE experiment at the DA$\Phi$NE $e^+e^-$ collider. A two-step signal selection strategy is used, exploiting first kinematic variables and then time-of-flight measurements. Data control samples of $K_L \to \pi e u$ decays are used to evaluate signal selection efficiencies. Normalizing the selected sample to the $K_S \to \pi^+ \pi^-$ decay events the result for the branching fraction is $B(K_S \to \pi e u) = (7.211 \pm 0.046_{stat} \pm 0.052_{syst}) × 10^{−4}$. The combination with our previous measurement gives $B(K_S\to \pi e u) = (7.153 \pm 0.037_{stat} \pm 0.043_{syst} ) x 10^{-4} = (7.153 \pm 0.057) x 10^{-4}$. From this value we derive $f_+ (0)|V_{us} |=0.2170 \pm 0.0009$.

Measurement of the branching fraction for the decay $B \to K^{\ast}(892)\ell^+\ell^-$ at Belle II

Abstract: We report a measurement of the branching fraction of B → K ∗ (892) (cid:96) + (cid:96) − decays, where (cid:96) + (cid:96) − = µ + µ − or e + e − , using electron-positron collisions recorded at an energy at or near the Υ (4 S ) mass and corresponding to an integrated luminosity of 189 fb − 1 . The data was collected during 2019–2021 by the Belle II experiment at the SuperKEKB e + e − asymmetric-energy collider. We reconstruct K ∗ (892) candidates in the K + π − , K 0 S π + , and K + π 0 final states. The signal yields with statistical uncertainties are 22 ± 6, 18 ± 6, and 38 ± 9 for the decays B → K ∗ (892) µ + µ − , B → K ∗ (892) e + e − , and B → K ∗ (892) (cid:96) + (cid:96) − , respectively. We measure the branching fractions of these decays for the entire range of the dilepton mass, excluding the very low mass region to suppress the B → K ∗ (892) γ ( → e + e − ) background and regions compatible with decays of charmonium resonances, to be

First Measurement of the B^{+}→π^{+}π^{0}π^{0} Branching Fraction and CP Asymmetry.

Abstract: We study B^{+}→π^{+}π^{0}π^{0} using 711 fb^{-1} of data collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We measure an inclusive branching fraction of (19.0±1.5±1.4)×10^{-6} and an inclusive CP asymmetry of (9.2±6.8±0.7)%, where the first uncertainties are statistical and the second are systematic, and a B^{+}→ρ(770)^{+}π^{0} branching fraction of (11.2±1.1±0.9_{-1.6}^{+0.8})×10^{-6}, where the third uncertainty is due to possible interference with B^{+}→ρ(1450)^{+}π^{0}. We present the first observation of a structure around 1 GeV/c^{2} in the π^{0}π^{0} mass spectrum, with a significance of 6.4σ, and measure a branching fraction to be (6.9±0.9±0.6)×10^{-6}. We also report a measurement of local CP asymmetry in this structure.

Precise measurement of Γ( K S → π + π − ( γ )) / Γ( K S → π 0 π 0 ) with the KLOE detector at DAΦNE

Abstract: = Γ( K S → π + π − ( γ )) / Γ( K S → π 0 π 0 ) has been measured with the KLOE detector. The result is R πS = 2 . 2555 ± 0 . 0012 stat ± 0 . 0021 syst - stat ± 0 . 0050 syst , which is in good agreement with the previously published result based on the KLOE data sample from the year 2000. The average of the KLOE results is R πS = 2 . 2549 ± 0 . 0054, reducing the total error by a factor of three, to 0 . 25%.

Search for the decay <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>η</mml:mi><mml:mo>′</mml:mo></mml:msup><mml:msubsup><mml:mi>K</mml:mi>

Abstract: We report the results of the first search for the decay Bs0→η′KS0 using 121.4 fb−1 of data collected at the ϒ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We observe no signal and set a 90% confidence-level upper limit of 8.16×10−6 on the Bs0→η′KS0 branching fraction.Received 5 January 2022Accepted 13 September 2022DOI:https://doi.org/10.1103/PhysRevD.106.L051103Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadronic decaysParticle decaysParticle phenomenaRare decaysParticles & Fields

Determination of $|V_{ub}|$ from untagged $B^0\to\pi^- \ell^+ \nu_{\ell}$ decays using 2019-2021 Belle II data

Abstract: We present an analysis of the charmless semileptonic decay B 0 → π − (cid:96) + ν (cid:96) , where (cid:96) = e, µ , from 198.0 million pairs of B ¯ B mesons recorded by the Belle II detector at the SuperKEKB electron-positron collider. The decay is reconstructed without identifying the partner B meson. The partial branching fractions are measured independently for B 0 → π − e + ν e and B 0 → π − µ + ν µ as functions of q 2 (momentum transfer squared), using 3896 B 0 → π − e + ν e and 5466 B 0 → π − µ + ν µ decays. The total branching fraction is found to be (1 . 426 ± 0 . 056 ± 0 . 125) × 10 − 4 for B 0 → π − (cid:96) + ν (cid:96) decays, where the uncertainties are statistical and systematic, respectively. By fitting the measured partial branching fractions as functions of q 2 , together with constraints on the nonperturbative hadronic contribution from lattice QCD calculations, the magnitude of the

Authoritarian Rule and the Weaponisation of Natural Disasters: The Case of Myanmar from Cyclone Nargis to the COVID-19 Pandemic (2008–2021)

Abstract: Myanmar’s 2021 military coup paved the way for a ruthless weaponisation of the COVID-19 pandemic, aimed at crushing opposition groups and ethnic minorities who opposed the army’s power grab. The manipulation of natural disasters for political purposes, however, is nothing new for Burmese praetorian regimes, which employed a similar strategy in the aftermath of the 2008 Cyclone Nargis in order to further marginalise and subjugate their internal enemies. To a large extent, such a callous decision stems from the powerful political implications brought about by natural disasters, which are perceived by authoritarian leaders as exogenous shocks capable of triggering a process of heightened popular contestation and regime change. In the case of Myanmar, this specific fear thus persuaded military rulers to weaponise the impact of natural calamities and health crises as part of a longstanding counterinsurgency playbook, centred on the so-called ‘four cuts’ doctrine. As a result, those who do not conform with the Bamar-Buddhist image of Myanmar professed by the army—or dare to criticise its dominant position in Burmese politics—have been deliberately excluded from post-disaster relief efforts, in what appears as a further testament of the junta’s unwavering resolve in retaining the reins of power. Building upon the existing literature on the political implications of natural hazards in authoritarian settings, the following article sheds light on the drivers and rationale that persuaded Myanmar’s Generals to weaponise humanitarian crisis against ethnic minorities and opposition forces, by looking at the two case-studies provided by Cyclone Nargis and the COVID-19 pandemic.

Searching for η → γγγ decay The KLOE Collaboration

Abstract: Data collected by the KLOE experiment in years 2001/2002 for a total integrated luminosity of 410 pb − 1 , corresponding to 17 million of produced η ’s from the Φ → ηγ radiative decay, have been analyzed to look for the C-violating decay η → γγγ . The signal is searched in events with 4 photons in the final state by using the spectrum of the most energetic photon. The background is evaluated from the data themself, doing a fifth degree polynomial fit outside the signal region, and extrapolating inside it. No signal has been observed and taking into account a selection efficiency ǫ = 20 . 3% we get from a likelihood fit Br( η → γγγ ) ≤ 1 . 6 × 10 − 5 at 95% CL. The procedure has a systematic ambiguity at the 35 % level.

Search for the radiative penguin decays <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>B</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msubsup><mml:mi>K</mml:mi><mml:mi>S</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:msubsup

Abstract: We report results from the first search for the rare penguin-dominated decay mode B0→KS0KS0γ, which can result from the production of tensor mesons f(1270) and f′(1525) in association with a photon. The search uses the full data sample of 772×106 BB¯ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. No statistically significant signals are observed in the KS0KS0 invariant mass range 1 GeV/c2

Search for charged lepton flavor violating decays of Υ(1 S ) The Belle Collaboration

Abstract: : We present a search for the charged lepton-flavor-violating decays Υ(1 S ) → (cid:96) ± (cid:96) (cid:48)∓

Studies of K 0 S decays with the KLOE detector at DAΦNE The KLOE Collaboration :

Abstract: The KLOE detector at DAΦNE , the Frascati φ-factory, has collected about 30 pb by the end of year 2000. The φ(1020) meson decays about 34% of the times into a K0L-K 0 S pair; DAΦNE is therefore an exceptional source of almost monochromatic, tagged K0S particles, allowing for detailed studies of their more rare decays. The above mentioned integrated luminosity corresponds to about 30 millions produced K0S. In KLOE the presence of a K0S is easily tagged by the observation of the corresponding K0L impinging onto the electromagnetic calorimeter before decay. Thanks to this technique we have performed a preliminary measurement of the ratio of the partial decay widths of the K0S into two charged and two neutral pions: B(K0S → π π)/B(KS → π π) = 2.23 × (1 ± 0.35× 10 (stat) ± 1.5× 10 (syst) ). We have also observed several hundreths semileptonic decays of the K0S by far the largest sample of this decay mode ever observed by any experiment so far. The preliminary estimate of the corresponding branching ratio is B(K0S → π eν) = (6.8 ± 0.3 (stat))×10; systematic effects are still under study and are presently estimated to be at the few percent level.