| 1. |
- Soffitta, Paolo, et al.
(författare)
-
XIPE : the X-ray imaging polarimetry explorer
- 2013
-
Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 36:3, s. 523-567
-
Tidskriftsartikel (refereegranskat)abstract
- X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017. The proposal was, unfortunately, not selected. To be compliant with this schedule, we designed the payload mostly with existing items. The XIPE proposal takes advantage of the completed phase A of POLARIX for an ASI small mission program that was cancelled, but is different in many aspects: the detectors, the presence of a solar flare polarimeter and photometer and the use of a light platform derived by a mass production for a cluster of satellites. XIPE is composed of two out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD) filled with a He-DME mixture at their focus. Two additional GPDs filled with a 3-bar Ar-DME mixture always face the Sun to detect polarization from solar flares. The Minimum Detectable Polarization of a 1 mCrab source reaches 14 % in the 2-10 keV band in 10(5) s for pointed observations, and 0.6 % for an X10 class solar flare in the 15-35 keV energy band. The imaging capability is 24 arcsec Half Energy Width (HEW) in a Field of View of 14.7 arcmin x 14.7 arcmin. The spectral resolution is 20 % at 6 keV and the time resolution is 8 mu s. The imaging capabilities of the JET-X optics and of the GPD have been demonstrated by a recent calibration campaign at PANTER X-ray test facility of the Max-Planck-Institut fur extraterrestrische Physik (MPE, Germany). XIPE takes advantage of a low-earth equatorial orbit with Malindi as down-link station and of a Mission Operation Center (MOC) at INPE (Brazil). The data policy is organized with a Core Program that comprises three months of Science Verification Phase and 25 % of net observing time in the following 2 years. A competitive Guest Observer program covers the remaining 75 % of the net observing time.
|
|
| 2. |
- Kattge, Jens, et al.
(författare)
-
TRY plant trait database - enhanced coverage and open access
- 2020
-
Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
-
Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
|
|
| 3. |
- Moretti, M., et al.
(författare)
-
Vector-Boson Production of Light Higgs Pairs in 2-Higgs Doublet Models
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- At the Large Hadron Collider, we prove the feasibility to detect pair production of the lightest CP-even Higgs boson h of Type II 2-Higgs Doublet Models through qq(') -> qq(')hh (vector-boson fusion). We also show that, through the hh -> 4b decay channel in presence of heavy-flavour tagging, further exploiting forward/backward jet sampling, one has direct access to the lambda Hhh triple Higgs coupling - which constrains the form of the Higgs potential.
|
|
| 4. |
- Abdelalim, Ahmed Ali, et al.
(författare)
-
Di-photon decay of a light Higgs state in the BLSSM
- 2022
-
Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 985
-
Tidskriftsartikel (refereegranskat)abstract
- In the context of the B - L Supersymmetric Standard Model (BLSSM), we investigate the consistency of a scenario with a light Higgs boson with mass in the range 94 - 98 GeV and a Standard Model (SM) Higgs state at 125 GeV with the results of a search performed by the CMS Collaboration in the di-photon channel primarily involving data at an integrated luminosity of 35.9 fb-1 and an energy of root s = 13 TeV. In this study, we present a Monte Carlo (MC) analysis of signal and background mimicking the experimental one and showing acceptable consistency with data, at both the integral and differential level.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.
|
|
| 5. |
- Accomando, E., et al.
(författare)
-
LHC data interpretation within the 2HDM type II via a new analysis toolkit
- 2022
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 105:11
-
Tidskriftsartikel (refereegranskat)abstract
- We review the status of the 2-Higgs doublet model (2HDM) type-II, in the light of the current experimental results and various theoretical consistency conditions. Compared to the existing literature, in this paper, we apply for the first time a new method that can improve the standard procedure for setting bounds on the 2HDM parameter space, as no experimental evidence has been found so far. Our new numerical framework, called MAGELLAN, and statistical techniques can be applied to any beyond the Standard Model (BSM) scenario. Here, we take as testing ground the 2HDM, particularly as it is physically interesting and moreover characterized by a far from trivial multidimensional parameter space where the effectiveness of the new methods can be proved. MAGELLAN uses a Markov chain Monte Carlo technique for scanning the parameter space and leverages the use of data processing and visualisation methods, allowing the user to perform inference on the model in a complete and efficient way. The novelty of the proposed method is that the parameter space of any BSM theory can be projected onto any bidimensional plane while still retaining all underlying attributes of those points, so that it is possible to investigate the associations between the properties of the various lower dimensional subspaces of the complete parameter space. The MAGELLAN's website interactive dashboards can be accessed via a public link. Through this website, the user can explore the full parameter space and exploit the phenomenological features of a BSM model with ease.
|
|
| 6. |
- Akeroyd, A. G., et al.
(författare)
-
Slight excess at 130 GeV in search for a charged Higgs boson decaying to a charm quark and a bottom quark at the Large Hadron Collider
- 2022
-
Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 49:8
-
Tidskriftsartikel (refereegranskat)abstract
- Searches for a charged Higgs boson (H-+/-) decaying to a charm quark and a bottom quark (H +/- -> cb) have been carried out at the Large Hadron Collider (LHC) in the decay of top quarks (t -> H(+/-)b). In a recent search by the ATLAS collaboration (with all run II data, 139 fb(-1)) a local excess of around 3 sigma has been observed, which is best fitted by a charged Higgs boson with a mass (m(H)+/-) of around 130 GeV and a product of branching ratios (BRs) given by BR(t -> H(+/-)b) x BR(H-+/- -> cb) = 0.16% +/- 0.06%. In the context of two-Higgs-doublet models (2HDM) with independent Yukawa couplings for H-+/- we present the parameter space for which this excess (assuming it to be genuine) can be accommodated, taking into account the limits from LHC searches for H-+/- -> cs and H-+/- -> tau nu at m(H)+/- = 130 GeV and the constraint from b -> s gamma. It is then shown that such an excess cannot be explained in 2HDMs with natural flavour conservation, but can be accommodated in the flipped three-Higgs-doublet model (3HDM) and in the aligned 2HDM (A2HDM). Upcoming searches with 139 fb(-1) in the channels H-+/- -> cb (CMS), H-+/- -> cs (ATLAS/CMS) and H-+/- -> tau nu (ATLAS/CMS) will determine if the excess is the first sign of an H-+/- with m(H)+/- = 130 GeV.
|
|
| 7. |
- Akeroyd, A. G., et al.
(författare)
-
The decay A(0) -> h(0)Z(*) in the inverted hierarchy scenario and its detection prospects at the large hadron collider
- 2023
-
Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 50:9
-
Tidskriftsartikel (refereegranskat)abstract
- Searches are being carried out at the large hadron collider (LHC) for the decay of the CP-odd scalar (A(0)) in two-Higgs-doublet models (2HDMs) with natural flavour conservation (NFC) in the channel A(0) -> h(0)Z (with m(h)(0) = 125 GeV and Z on-shell). In the absence of any signal, limits on the parameter space of [tan beta, cos(beta - alpha), mA0] in each 2HDM are derived for m(A)(0) > 225 GeV. In this work, we consider the scenario of inverted hierarchy with m(h)(0) < 125 GeV and m(H)(0) = 125 GeV in which the decay A(0) -> h(0)Z(*) (i.e. including the case of an off-shell Z) can have a large branching ratio in the 2HDM (Type I) for m(A)(0) < 225 GeV. We calculate the signal cross section sigma(gg -> A(0)) ' BR(A(0) -> h(0)Z (*)) ' BR(h(0) -> b<(b)over bar>) in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy (m(h)(0) = 125 GeV) that is currently being searched for at the LHC. For the experimentally unexplored region m(A)(0) < 225 GeV it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for A(0) -> h(0)Z(*) to probe the scenario of inverted hierarchy.
|
|
| 8. |
- Ali, Murad, et al.
(författare)
-
TeV-scale leptoquark searches at the LHC and their E6SSM interpretation
- 2023
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :3
-
Tidskriftsartikel (refereegranskat)abstract
- We perform a model-independent search for leptoquarks (LQs) at the Large Hadron Collider through their pair-production and subsequent decay into tt¯ττ intermediate states. We show that, assuming full luminosity of the Run 2, a fully hadronic signal emerging from this intermediate state can surpass in sensitivity the established searches relying on leptons in the final state. Our conclusion is supported by a thorough Monte-Carlo analysis, and we advocate the deployment of our proposed search channel in the proper experimental setting of the Run 3. Furthermore, in order to highlight the full scope of this approach for constraining LQ theories, we interpret our results in the context of the string-inspired Exceptional Supersymmetric Standard Model, which naturally predicts the S1-type scalar LQ states that we analyse here.
|
|
| 9. |
|
|
| 10. |
- Alwall, Johan, et al.
(författare)
-
The pp -> tbH+/- process at the Tevatron in Herwig and Pythia simulations
- 2004
-
Ingår i: The European Physical Journal C: Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 39, s1, s. s37-s39
-
Tidskriftsartikel (refereegranskat)abstract
- Charged Higgs boson production in association with a top quark could be the first indication of the existence of Higgs particles. The Tevatron Run-II started data-taking in April 2001 at $\sqrt s=1960$ GeV and could probe the existence of a charged Higgs boson beyond the current mass limit. We study the $\rm p\bar p \rightarrow tbH^\pm$ production process with Monte Carlo simulations in HERWIG and PYTHIA, comparing expected cross sections and basic selection variables.
|
|
