dataesr/scientific-paragraphs-categorization huggingface dataset:
Geometry of the Disk: The Argument of Periastron There has been much debate in the literature over the argument of periastron, ω f , of the Fomalhaut ring. Acke et al. (2012)  find ω f = 1 • ± 6 • based upon the location of the observed pericenter glow along the disk major axis. However, the resolution of the Herschel 70 µm image is not high enough to detect an offset in the stellar position off the disk major axis by a few AU. Kalas et al. (2013)  determine a value of 29. • 6 ± 1. • 3 by fitting only for the offset of the expected stellar position from the disk centroid. Boley et al. (2012)  are unable to constrain the argument of periastron, since they only image half of the belt with ALMA. Our new ALMA data provides the first resolved image of emission from both the complete outer disk and the central star with high enough angular resolution to determine an offset of the star from the disk centroid.
Photo-nuclear interactions are relevant in many research fields of both fundamental and applied physics and, for this reason, accurate Monte Carlo simulations of photo-nuclear interactions can provide a valuable and indispensable support in a wide range of applications (i. e from the optimisation of photo-neutron source target to the dosimetric estimation in high energy accelerator, etc). Unfortunately, few experimental photo-nuclear data are available above 100 MeV, so that, in the high energy range (from hundreds of MeV up to GeV scale), the code predictions are based on physical models. The aim of this work is to compare the predictions of relevant observables involving photon-nuclear interaction modelling, obtained with GEANT 4 and FLUKA, to experimental data (if available), in order to assess the code estimation reliability, over a wide energy range.
We have started an assessment of the reliability of predictions of GEANT4  [1]  and FLUKA  [2]  and some preliminary results of this complex work (still in progress) are presented and discussed in this report. The comparison of measured observables with simulated ones, in a high energy scenario for which experimental data are available, is also presented. The comparison relies on suitable quantitative validation tests, based e-mail: lina. quintieri@enea. it on statistical data analysis methods (i. e. χ 2 test). The difference in prediction capabilities of different Monte Carlo codes can originate mainly at two different levels, that represent the sequential steps of the physics implementation inside the code itself: • first level: different used data library cross sections • second level: different reconstruction of the secondary final state (energy spectra, angular distribution, etc) As first step, the investigative analysis (to find the reason of the possible differences) foresees to compare the cross sections used in the specified codes with the IAEA recommended photonuclear cross sections  [3] , mainly focusing on selected materials, widely used in high energy accelerator context (lead, tungsten, copper, etc).
We want to individuate and possibly address the solution of some critical implementation in GENAT4 (if any, after careful investigation) or eventually to promote an improvement of the photo-nuclear implementation inside the code itself. The first step of the analysis is the comparison of the photo-nuclear cross sections used in each code with the evaluated IAEA photo-nuclear data, starting from those cases in which we are more directly interested. Anyway, the complete analysis will foresee to compare as exhaustively as possible all the photo-nuclear cross sections and finally to focus on the fitting procedure characteristic of each code to extend the cross sections in the energy range, when experimental data are missing or to evaluate (according the different parameterisation applied in each code) the cross sections for those cases non included in the data library.
Implementation of Photonuclear physics in Geant4 Photo-nuclear interaction cross sections in GEANT4 database are approximated for all the nuclei and all the energies (from hadron production threshold to about 50 GeV). The GEANT4 database is made of parameterised cross sections of 51 nuclei (see Table  5  and Table  6 ). The cross section parameterisation in the different energy range is expressed as function of: the Atomic mass "A", the energy "e" and several other parameters that are calculated for a list of selected 14 nuclei and interpolated for all the other nuclei. The photonuclear cross sections are parameterised in the G4PhotoNuclearCrossSection: the evaluated data of the 51 nuclei are inserted as G4double arrays and the fit algorithms for the parameterisation of all the rest of nuclei (not included in the GEANT4 data base) are implemented according five energy regions, each corresponding to the physical process that dominates.
Implementation of Photo-nuclear physics in FLUKA An important upgrade for the photo-nuclear physics in FLUKA was done in 2005, when the data library was completed and extended in such a way that cross section data for 190 nuclides were made available. If experimental cross sections were not available, then Lorentz fits of 1 Note that all these elements are used also in the fitting procedure to reconstruct the GDR in the low energy region (together with the elements of Table  6 ) with the exception of 2H and 3He that are used only for the high energy cross-section interpolation the existing data could be used to derive them: for Z> 29 typically the parameters of the fit (as peak energy, peak height and width) are taken from the Atlas of Dietrich and Berman  [8]  except for Pr, Au and Pb for which the parameters used are those published by Berman et al  [9].
) often show discrepancies that must be resolved in the evaluation process • Most of the existing spectral measurements are for bremsstrahlung, while only the measurements from mono-energetic sources give emission spectra directly useful for cross-section evaluations • Photo-nuclear data are isotopic in nature, the cross sections showing irregular dependence on atomic number (Z) and atomic mass (A). Thus while photo-atomic data are readily tabulated by element, photo-nuclear data must be tabulated for each isotope of an element This explains why a relatively complete photo-nuclear data file became available only in 2000  [3]  in order to be promptly distributed to the whole scientific community. The IAEA Compilation and Evaluation of Photonuclear Data for Applications, released in 2000 in ENDF format for 164 isotopes, represents still today the internationally recognised data file of evaluated photo nuclear cross-sections for use in transport simulation codes.
The term evaluated means that cross-sections or other data have been optimised: 1) assessing the most probable value from a collection of experimental data; 2) performing theoretical calculations with models and parameters that have been optimised to experimental data or 3) using a combination of experimental data and theoretical calculation to ascertain best or recommended values. Taking into account the previous considerations, the IAEA recommended evaluated photo-nuclear data have been assumed, in this work, as the reference respect to which evaluate the conformity or eventual remarkable differences of the implemented photo-nuclear cross section of GEANT4 and FLUKA. The photo-neutron cross sections to which we refer in the tests are the "total photo-absorption"ones. For sake of clarity, the photo-neutron cross section definition is reported in the following formula  [3] : σ(γ, sn) = σ(γ, n) + σ(γ, np) + σ(γ, 2n) + σ(γ, 2np) +σ(γ, n2p) + σ(γ, 3n).
Natural tungsten photo-absorption cross-sections Geant4 cross section library includes data for the following two tungsten isotopes: 184W and 186 W up to 105 MeV, while for higher energy the cross section values are obtained by fitting the data of 14 listed nuclides in Table  5  for which the cross section is reported up to 50 GeV, by means of parameters that are obtained as a function of 'A', 'Z' and 'energy' according suitable models in different energy range. In order to extract the cross section for the natural tungsten, a proper application has been developed, in which only the photo-nuclear physics is activated. The Kolmogorov-Smirnov test with null hypothesis affirming that data vectors GEANT4 and IAEA are from populations with the same distribution, at the 1% significance level, produced the rejection of the null hypothesis.
Natural zinc photo-absorption cross-sections In this preliminary analysis, the natural Zn total photoabsorption cross sections, used in GEANT4 and FLUKA codes, have been also compared to the corresponding IAEA evaluated values. In the documentation  [12] showing the approximation of the photo-nuclear interaction cross section for all the elements whose nuclear data are tabulated in the G4PhotoNuclearCrossSection class, the nat-Zn is the only missing case. Finally, Kolmogorov-Smirnov Test with significance level alpha=0. 01, and null Hypothesis affirming that GEANT4 estimates the recommended IAEA distribution is rejected.
Conclusion and future plan Statistical methods are used both to quantify the consistency of simulations based on individual Monte Carlo codes with experimental data and to establish the significance of differences. At this stage of the analysis and for the specific case of measurements carried in high energy range at DaΦne Beam Test Facility, FLUKA predictions show a better agreement with experimental data, respect to GEANT4. Anyway in FLUKA the original cross section database, contrarily to GEANT4, are not accessible directly by the user. In order to investigate the reason of why GEANT4 underestimates the neutron yield for the n@BTF experiment, a rigorous analysis of comparison of the implemented photonuclear data for the concerned materials with the IAEA evaluated data has been started. The Kolmogorov-Smirnov tests performed for W, Pb an Zn to check the compliance of the GEANT4 with the evaluated and recommended IAEA cross sections, produced negative results (contrarily to FLUKA).
Acknowledgements Photo-nuclear calculations are typically complex and computationally intensive, since they require extensive libraries of isotopic data, high statistics simulations and, often the application of adequate biasing techniques, due to the low photo-neutron cross sections. In order to produce accurate predictions for the photo-neutron yields, large number of events are simulated and variance reduction methods are applied. The ability to exploit techniques for parallel calculations is fundamental to achieve statistically significant results within a reasonable time. The computing resources and the related technical support used for this work are provided by the  CRESCO/ENEAGRID High Performance Computing infrastructure [13 ]. The CRESCO/ENEAGRID infrastructure is funded by  ENEA , the  Italian National Agency for New Technologies, Energy and Sustainable Economic Development  and by national and European research programs.
The structure of the film used in those studies was Pt(5 or 1. 5)/Co(0. 3)/Ni(0. 7)/Co(0. 15)/TaN (5)  and in that work a longitudinal magnetic field was applied to cancel the effective field at the DW due to the DMI and which prevented the current-induced DW motion. This has been referred to as the "crossing field" and it is proportional to the DMI as H cr = D eff /(µ 0 M s ∆) where ∆ is the DW width parameter. The crossing field was observed to decrease with ultrathin sub-nanometric Au spacer layers inserted at the lower Pt/Co interface. In Fig. 3  the DMI variation (expressed as a percentage) obtained here is compared to the results from Ryu et al. A broadly similar variation was observed for both methods for all curves for the available SL thicknesses up to 0. 5 nm. In other words, estimates of the IDMI strength as a function of SL thickness from two completely different experimental techniques correlate well over the SL thicknesses available for both datasets.
We have achieved this by simultaneously fitting the reflectivity alongside the spin asymmetry, thereby ensuring all the structural parameters are consistent with both datasets. Furthermore the resonant scattering corrections, f and f as well as the magnetic scattering factors m and m , which describe the resonant behaviour of the Pt, were determined from the sample with no SL and fixed for the other samples in the series. This approach allows for direct comparisons to made between the samples, but means an absolute magnetic moment can not be established. However, it is the relative change in magnetism as a function of SL that we are interested in.
As can be seen in Supplementary Fig. 7  both phonon spectra are absolutely symmetric, the Stokes and anti-Stokes lines in the direct (solid red) and frequency-inverted (dotted blue) spectra are perfectly overlapping ( f S = f AS ), whilst the magnon-related line demonstrates a clearly seen asymmetry ( f S < f AS ). It was routine in measurements to place the analyser in front of the Fabry-Perot interferometer to improve the signal to noise ratio. Moreover, to double check it, we were taking advantage of the fact that the sign of delta is changed if the saturating magnetic field polarity is inversed. Spectra were obtained after counting photons for typically 12 hours to improve the quality of the raw data BLS spectra. Numerical simulations of the shape of the BLS spectra of SW in the DE geometry were very helpful for improving the accuracy and reliability of our measurements.
Acknowledgements Funding is acknowledged from  EPSRC  for the studentship for  R. M. Rowan-Robinson  ( 1212684 ) and Grant Ref. EP/L000121/1. We acknowledge the funding for beam time awarded on the EPSRC-funded XMaS Beamline at the  ESRF  for the PIM measurements and we are grateful for the contributions of  Dr Laurence Bouchenoire at XMaS  and  Dr Matts Björk  for insights and support with GenX analysis of the x-ray reflectivity. Data supporting this work is available at http://dx. doi. org/10. 15128/r1bv73c0401.
Acknowledgements We acknowledge discussions with Pascal Salières and  Willem Boutu. We acknowledge financial support from the  European Union  through the  EU-LASERLAB  ( SLIC 001682 ) and the  VOXEL FET , from the  French ministry of research  through the  2013 ANR grants "NanoImagine", 2014 "IPEX", 2016 "HELLIX" and from the C'NANO research program  through the  NanoscopiX grant , and the  LABEX "PALM" through the grants. "Plasmon-X" and "HILAC". We acknowledge the financial support from the french  ASTRE program  through the  "NanoLight" grant. We acknowledge the financial support from the  Swedish Research Council (Vetenskapsrådet)  grant number  637-2013-439/D0043901  and the  Swedish Foundation for International Cooperation in Research and Higher Education (STINT). Financial support by the  Deutsche Forschungsgemeinschaft , grant  KO 3798/4-11  and from  Lower Saxony  through " Quanten-und Nanometrologie" (QUANOMET) , project  NanoPhotonik  are acknowledged.
clara. marvaz@gmail. com lites NGC185 and NGC147. Nevertheless, with the advent of the Hubble Space Telescope (HST) it was possible to reach well below the HB. This allowed the first determination of the properties of RRL stars in the M31 field and its satellites. Based on WFPC2 data, the discovery of RRL stars was reported in And I  (Da Costa et al. 1996) , And II  (Da Costa et al. 2000)  and And III  (Da Costa et al. 2002). The population of variable stars detected in the three galaxies were later analyzed in detail by  Pritzl et al. (2004, And II)  and  Pritzl et al. (2005, And I and And III). Additionally, And VI was studied by  Pritzl et al. (2002)  on the basis of data of comparable quality. Since then, the number of known satellites of M31 has increased dramatically, primarily due to the PAndAS survey  (McConnachie et al.
2017)  while the first results concerning the SFH of And II and And XVI were presented in  Weisz et al. (2014)  and  Monelli et al. (2016). In order to complement these previous studies, this paper focuses on the study of variable stars -mainly RRLs, but also Anomalous Cepheids (ACs)-present in the six ISLAndS galaxies. The data obtained within the framework of this project have allowed us to increase by a factor 2-3. 4 the number of known variable stars and the quality of the light curves in And I, And II, and And III compared to previous studies  (Pritzl et al. 2004 (Pritzl et al. , 2005)). On the other hand, this project provides the first discoveries of variable stars in And XV, And XVI, and And XXVIII, although an analysis of the RRL in AndXVI within the context of its SFH has been presented in  Monelli et al.
OBSERVATIONS AND DATA REDUCTION Table  1  presents a compilation of updated values for the position of the center (RA and Dec, column 2 and 3, respectively), absolute M V magnitude (column 4), reddening (E(B-V ), column 5) and structural parameters -ellipticity (ǫ, column 6), position angle (PA, column 7), half-light radius (r h , column 8) and tidal radius (r t , column 9)-for each of the six observed galaxies under the ISLAndS project (hereafter called ISLAndS galaxies). The data for these six ISLAndS galaxies have been obtained under proposals GO-13028 and GO-13739, for a total of 111 HST orbits. They consist of one ACS pointing on the central region and a WFC3 parallel field (at 6 ′ from the ACS center) for each galaxy. For further details about the ACS and WFC3 field location, the reader is referred to Figure  4  by  Skillman et al.
of the six ISLAndS galaxies and of a sample of MW satellites. The latter consists of revised data for Carina, Fornax, Sculptor, Draco, and Leo II from the updated catalogs available in P. B. Stetson's database  (Stetson 2017, priv. comm. ). These studies are part of an ongoing series of papers on variable stars in globular clusters and dwarf galaxies by ourselves and our collaborators  (Stetson et al. 2014; Braga et al. 2015; Coppola et al. 2015; Martínez-Vázquez et al. 2016b; Braga et al. 2016; Fiorentino et al. 2017). The value of the R HB index was calculated in a homogeneous way considering only stars within 1 half-light radius, r h. This was possible for all of the galaxies except for And I and II, since the ACS only covers a fraction of such area (see Figure  3 ). In the case of the MW satellites, we estimated and subtracted the Galactic field-star contribution using a proper control field in the outskirts of each object.
SUMMARY AND FINAL REMARKS In this paper we have analyzed multi-epoch HST data for six dSphs satellites of M31 in order to study their population of variable stars. The main findings of the current study are: • We have detected 895 variable stars in And I, II, III, XV, XVI, and XXVIII: 678 of them are new discoveries. In particular, we classified 870 RRL stars, 15 ACs, 3 EB and 7 field variable stars (5 of them probably belonging to the GSS of M31). Interestingly, no ACs were found in And I despite being the second most massive dwarf in our sample, which we interpret as a hint of the fast chemical enrichment of this galaxy. • Pulsational properties (period, amplitude, mean magnitude) were derived for all detected variables. Moreover, we provide all the light curves and time series photometry.
• Using the properties of RRL stars, we derived new homogeneous distances to the six galaxies using three different methods: the period-Wesenheit relation, the metallicity-luminosity relation and the first overtone blue edge method. A fourth independent estimate was derived using the tip of the RGB for the three most populated systems. We find a satisfactory agreement both between different methods and with most of the estimates available in the literature. It is worth noting Light curves of member AC stars for four of the six ISLAndS galaxies in the F 475W (black) and F 814W (gray) bands. Periods (in days) are given in the lower-right corner, while the name of the variable is displayed at the top of each panel. Open symbols show the data for which the uncertainties are larger than 3-σ above the mean error of a given star; these data were not used in periods and mean magnitudes calculations.
Finally, regarding RRL stars in the M31 satellites, the large number of dwarf galaxies discovered in this system during the last few years remain largely unexplored. The advent of the wide-field imaging capability of telescopes, such as WFIRST (with a field of view roughly 100 times greater than that of HST), could substantially accelerate these studies and offer us the possibility to understand the similarities and differences between the two systems of the Local Group: MW and M31 satellites. The authors thank the anonymous referee for the useful comments which helped to improve the manuscript. This research made extensive use of NASA's Astrophysics Data System Bibliographic Services and the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the Na-tional Aeronautics and Space Administration.
A total of 94, 69 and 54 stars (out of 100, 73 and 56 in their catalogues) were recovered for And I, And II and And III, respectively. The cross-identifications made between our catalogues and Pritzl's are shown in Tables C13, C14, C15. The small fraction of stars that were not recovered either appear as non variable in our data or fall in the ACS gap (see the column "Notes" of Tables C13, C14, C15). We note that the matching was complicated by the fact that the coordinates listed in the Pritzl catalogs were significantly offset, with different offsets for each WFPC2 chip, in particular in the case of And III. The comparison discloses a general good agreement (53% of the stars within a difference of 0. 05 days and 80% within 0. 1 days) though with a few outliers for which the period is significantly discrepant (20% have a difference larger than 0.
[11]. With the diphoton trigger, this channel is more sensitive in the low E miss T region than the channel with the SM Higgs boson decaying into a pair of b-quarks, which relies on the high E miss T trigger. This paper presents an updated search for DM particles (χ) associated with the SM Higgs boson (h) decay to a pair of photons using 36. 1 fb -1 of pp collision data collected at √ s = 13 TeV during 2015 and 2016, where both the integrated luminosity and the center-of-mass energy are significantly higher than in the previously published ATLAS analysis  [7]. Three benchmark models are considered in this analysis. The leading-order (LO) Feynman diagrams representing the production of h plus E miss T in two simplified models  [12]  are shown in Figs. 1(a ) and 1(b). In the first model, a massive vector mediator Z emits a Higgs boson and subsequently decays to a pair of Dirac fermionic DM candidates.
The DM mass (m χ ) is taken to be roughly half of the SM Higgs-boson mass to ensure on-shell decay of H → hχχ, and to suppress invisible decay modes of h, as described in Ref. [15]. While no assumptions are made here as to the nature of H, it can be viewed as a part of a 2HDM+χ scenario where H may be considered as the CP-even heavy scalar boson  [14]. This paper is organized as follows. Section 2 gives a brief description of the ATLAS detector. Section 3 describes the data set and the signal and background Monte Carlo (MC) simulation samples used. Section 4 explains the event reconstruction, while Section 5 outlines the optimization of the event selection and categorization. Section 6 summarizes the signal and background modeling. Section 7 discusses the experimental and theoretical systematic uncertainties that affect the results.