| 1. |
- Babusci, D., et al.
(författare)
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A new limit on the CP violating decay K-S -> 3 pi(0) with the KLOE experiment
- 2013
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 723:1-3, s. 54-60
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Tidskriftsartikel (refereegranskat)abstract
- We have carried out a new direct search for the CP violating decay K-S -> 3 pi(0) with 1.7 fb(-1) of e(+)e(-) collisions collected by the KLOE detector at the Phi-factory DA Phi NE. We have searched for this decay in a sample of about 5.9 x 10(8) KSKL events tagging the K-S by means of the K-L interaction in the calorimeter and requiring six prompt photons. With respect to our previous search, the analysis has been improved by increasing of a factor four the tagged sample and by a more effective background rejection of fake K-S tags and spurious clusters. We find no candidates in data and simulated background samples, while we expect 0.12 standard model events. Normalizing to the number of K-S -> 2 pi(0) events in the same sample, we set the upper limit on BR(K-S -> 3 pi(0)) <= 2.6 x 10(-8) at 90% C.L., five times lower than the previous limit. We also set the upper limit on the eta(000) parameter, vertical bar eta(000)vertical bar <= 0.0088 at 90% C.L., improving by a factor two the latest direct measurement. (c) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Babusci, D., et al.
(författare)
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Search for light vector boson production in e(+)e(-) -> mu(+)mu(-)gamma interactions with the KLOE experiment
- 2014
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 736, s. 459-464
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Tidskriftsartikel (refereegranskat)abstract
- We have searched for a light vector boson U, the possible carrier of a "dark force", with the KLOE detector at the DA Phi NE e(+)e(-) collider, motivated by astrophysical evidence for the presence of dark matter in the Universe. Using e(+)e(-) collisions collected with an integrated luminosity of 239.3 pb(-1), we look for a dimuon mass peak in the reaction e(+)e(-) -> mu(+)mu(-)gamma, corresponding to the decay U -> mu(+)mu(-). We find no evidence for a U vector boson signal. We set a 90% CL upper limit for the mixing parameter squared between the photon and the U boson of 1.6 x 10(-5) to 8.6 x 10(-7) for the mass region 520 < m(U) < 980 MeV.
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| 3. |
- Babusci, D., et al.
(författare)
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Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment
- 2014
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 730, s. 89-94
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Tidskriftsartikel (refereegranskat)abstract
- Neutral kaon pairs produced in phi decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process phi -> KSKL -> pi(+)pi(-)pi(+)pi(-) based on 1.7 fb(-1) of data collected by the KLOE experiment at the Frascati phi-factory DA Phi NE. The data are used to perform a Measurement of the CPT-violating parameters Delta a(mu) for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are: Delta a(0) = (-6.0 +/- 7.7(stat)+/- 3.1(syst)) X 10(-18) GeV, Delta a(x) = (0.9 +/- 1.5(stat)+/- 0.6(syst)) X 10(-18) GeV, Delta a(y) = (-2.0 +/- 1.5(stat)+/- 0.5(syst)) X 10(-18) GeV, Delta a(z) = (3.1 +/- 1.7(stat)+/- 0.5(syst)) X 10(-18) GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension. (C) 2014 The Authors. Published by Elsevier B.V.
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| 4. |
- Spinelli, L., et al.
(författare)
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Determination of reference values for optical properties of liquid phantoms based on Intralipid and India ink
- 2014
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Ingår i: Biomedical Optics Express. - : Optical Society of America. - 2156-7085. ; 5:7, s. 2037-2053
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Tidskriftsartikel (refereegranskat)abstract
- A multi-center study has been set up to accurately characterize the optical properties of diffusive liquid phantoms based on Intralipid and India ink at near-infrared (NIR) wavelengths. Nine research laboratories from six countries adopting different measurement techniques, instrumental set-ups, and data analysis methods determined at their best the optical properties and relative uncertainties of diffusive dilutions prepared with common samples of the two compounds. By exploiting a suitable statistical model, comprehensive reference values at three NIR wavelengths for the intrinsic absorption coefficient of India ink and the intrinsic reduced scattering coefficient of Intralipid-20% were determined with an uncertainty of about 2% or better, depending on the wavelength considered, and 1%, respectively. Even if in this study we focused on particular batches of India ink and Intralipid, the reference values determined here represent a solid and useful starting point for preparing diffusive liquid phantoms with accurately defined optical properties. Furthermore, due to the ready availability, low cost, long-term stability and batch-to-batch reproducibility of these compounds, they provide a unique fundamental tool for the calibration and performance assessment of diffuse optical spectroscopy instrumentation intended to be used in laboratory or clinical environment. Finally, the collaborative work presented here demonstrates that the accuracy level attained in this work for optical properties of diffusive phantoms is reliable.
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| 5. |
- Weng, S., et al.
(författare)
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MUSE-ALMA Haloes – VIII. Statistical study of circumgalactic medium gas
- 2023
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 519:1, s. 931-947
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of gas and metals in the circumgalactic medium (CGM) plays a critical role in how galaxies evolve. The MUSE-ALMA Haloes survey combines MUSE, ALMA, and HST observations to constrain the properties of the multiphase gas in the CGM and the galaxies associated with the gas probed in absorption. In this paper, we analyse the properties of galaxies associated with 32 strong HI Ly-α absorbers at redshift 0.2 ≲ z ≲ 1.4. We detect 79 galaxies within ±500 kms−1 of the absorbers in our 19 MUSE fields. These associated galaxies are found at physical distances from 5.7 kpc and reach star formation rates as low as 0.1 M⊙ yr−1. The significant number of associated galaxies allows us to map their physical distribution on the Δv and b plane. Building on previous studies, we examine the physical and nebular properties of these associated galaxies and find the following: (i) 27/32 absorbers have galaxy counterparts and more than 50 per cent of the absorbers have two or more associated galaxies, (ii) the HIHI column density of absorbers is anticorrelated with the impact parameter (scaled by virial radius) of the nearest galaxy as expected from simulations, (iii) the metallicity of associated galaxies is typically larger than the absorber metallicity, which decreases at larger impact parameters. It becomes clear that while strong HIHI absorbers are typically associated with more than a single galaxy, we can use them to statistically map the gas and metal distribution in the CGM.
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| 6. |
- Péroux, C., et al.
(författare)
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MUSE-ALMA haloes VII : survey science goals & design, data processing and final catalogues
- 2022
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 516:4, s. 5618-5636
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Tidskriftsartikel (refereegranskat)abstract
- The gas cycling in the circumgalactic regions of galaxies is known to be multi-phase. The MUSE–ALMA Haloes survey gathers a large multi-wavelength observational sample of absorption and emission data with the goal to significantly advance our understanding of the physical properties of such CGM gas. A key component of the MUSE–ALMA Haloes survey is the multi-facility observational campaign conducted with VLT/MUSE, ALMA, and HST. MUSE–ALMA Haloes targets comprise 19 VLT/MUSE IFS quasar fields, including 32 zabs <0.85 strong absorbers with measured N(H I) ≥1018 cm−2 from UV-spectroscopy. We additionally use a new complementary HST medium program to characterize the stellar content of the galaxies through a 40-orbit three-band UVIS and IR WFC3 imaging. Beyond the absorber-selected targets, we detect 3658 sources all fields combined, including 703 objects with spectroscopic redshifts. This galaxy-selected sample constitutes the main focus of the current paper. We have secured millimeter ALMA observations of some of the fields to probe the molecular gas properties of these objects. Here, we present the overall survey science goals, target selection, observational strategy, data processing and source identification of the full sample. Furthermore, we provide catalogues of magnitude measurements for all objects detected in VLT/MUSE, ALMA, and HST broad-band images and associated spectroscopic redshifts derived from VLT/MUSE observations. Together, this data set provides robust characterization of the neutral atomic gas, molecular gas and stars in the same objects resulting in the baryon census of condensed matter in complex galaxy structures.
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| 7. |
- Akola, J., et al.
(författare)
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Thiolate-Protected Au-25 Superatoms as Building Blocks: Dimers and Crystals
- 2010
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:38, s. 15986-15994
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Tidskriftsartikel (refereegranskat)abstract
- A particularly stable thiolate-protected gold nanocluster, Au-25(SR)(18), was structurally characterized from X-ray crystallography in 2008, and concomitantly its electronic and optical properties were analyzed via density functional theory. The robust geometry and a well-understood electronic structure of this cluster motivate explorations of properties of extended systems made out of Au-25(SR)(18) building blocks. As a first step in this direction, we analyze here structural, vibrational, electronic, and optical properties of the Au-25 cluster anion as it was observed in the crystalline environment and predict properties of cluster dimers, where the Au-25 units are linked together. via an aromatic dithiolate linker. We show that properties of each Au-25 unit of the dimer can be quite independently modified from the other by doping with a nonmagnetic (Pd) or magnetic (Mn) metal atom. We anticipate that material systems with interesting properties could be made from these building blocks, provided that a suitable chemistry for their controlled linking can be found.
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| 8. |
- Augustin, Ramona, et al.
(författare)
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MUSE-ALMA Haloes X : the stellar masses of gas-rich absorbing galaxies
- 2024
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Ingår i: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 528:4, s. 6159-6166
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Tidskriftsartikel (refereegranskat)abstract
- The physical processes by which gas is accreted onto galaxies, transformed into stars, and then expelled from galaxies are of paramount importance to galaxy evolution studies. Observationally constraining each of these baryonic components in the same system, however, is challenging. Furthermore, simulations indicate that the stellar mass of galaxies is a key factor influencing CGM properties. Indeed, absorption lines detected against background quasars offer the most compelling way to study the cold gas in the circumgalactic medium (CGM). The MUSE-ALMA Haloes survey is composed of quasar fields covered with VLT/MUSE observations, comprising 32 H I absorbers at 0.2 < z < 1.4 and 79 associated galaxies, with available or upcoming molecular gas measurements from ALMA. We use a dedicated 40-orbit HST UVIS and IR WFC3 broad-band imaging campaign to characterize the stellar content of these galaxies. By fitting their spectral energy distribution, we establish they probe a wide range of stellar masses: 8.1 < log (M∗/M⊙) < 12.4. Given their star formation rates, most of these objects lie on the main sequence of galaxies. We also confirm a previously reported anticorrelation between the stellar masses and CGM hydrogen column density N (H I), indicating an evolutionary trend where higher mass galaxies are less likely to host large amounts of H I gas in their immediate vicinity up to 120 kpc. Together with other studies from the MUSE-ALMA Haloes survey, these data provide stellar masses of absorber hosts, a key component of galaxy formation and evolution, and observational constraints on the relation between galaxies and their surrounding medium.
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| 9. |
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| 10. |
- Kacprzak, Sylwia M., et al.
(författare)
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Carbon starvation, senescence and specific mitochondrial stresses, but not nitrogen starvation and general stresses, are major triggers for mitophagy in Arabidopsis
- 2022
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8627 .- 1554-8635. ; 18:12, s. 2894-2912
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Tidskriftsartikel (refereegranskat)abstract
- Selective degradation of mitochondria by autophagy (mitophagy) is thought to play an important role in mitochondrial quality control, but our understanding of which conditions induce mitophagy in plants is limited. Here, we developed novel reporter lines to monitor mitophagy in plants and surveyed the rate of mitophagy under a wide range of stresses and developmental conditions. Especially carbon starvation induced by dark-incubation causes a dramatic increase in mitophagy within a few hours, further increasing as dark-induced senescence progresses. Natural senescence was also a strong trigger of mitophagy, peaking when leaf yellowing became prominent. In contrast, nitrogen starvation, a trigger of general autophagy, does not induce strong increases in mitophagy. Similarly, general stresses such as hydrogen peroxide, heat, UV-B and hypoxia did not appear to trigger substantial mitophagy in plants. Additionally, we exposed plants to inhibitors of the mitochondrial electron transport chain, mitochondrial translation and protein import. Although short-term treatments did not induce high mitophagy rates, longer term exposures to uncoupling agent and inhibitors of mitochondrial protein import/translation could clearly increase mitophagic flux. These findings could further be confirmed using confocal microscopy. To validate that mitophagy is mediated by the autophagy pathway, we showed that mitophagic flux is abolished or strongly decreased in atg5/AuTophaGy 5 and atg11 mutants, respectively. Finally, we observed high rates of mitophagy in etiolated seedlings, which remarkably was completely repressed within 6 h after light exposure. In conclusion, we propose that dark-induced carbon starvation, natural senescence and specific mitochondrial stresses are key triggers of mitophagy in plants. Abbreviations AA: antimycin A; ATG: AuToPhagy related; ConA: concanamycin A; DIS: dark-induced senescence; Dox: doxycycline; FCCP: carbonyl cyanide-p-trifluoromethoxyphenylhydrazone; GFP: green fluorescent protein; IDH1: isocitrate dehydrogenase 1; MB: MitoBlock-6; Mito-GFP: transgenic Arabidopsis line expressing a mitochondrially targeted protein fused to GFP; mtETC: mitochondrial electron transport chain; OXPHOS: oxidative phosphorylation; PQC: protein quality control; TOM20: Translocase of Outer Membrane 20.
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