86 research outputs found
Nature of the X(5568) : a critical Laplace sum rule analysis at N2LO
We scrutinize recent QCD spectral sum rules (QSSR) results to lowest order
(LO) predicting the masses of the BK molecule and (su)\bar(bd) four-quark
states. We improve these results by adding NLO and N2LO corrections to the PT
contributions giving a more precise meaning on the b-quark mass definition used
in the analysis. We extract our optimal predictions using Laplace sum rule
(LSR) within the standard stability criteria versus the changes of the external
free parameters (\tau-sum rule variable, t_c continuum threshold and
subtraction constant \mu). The smallness of the higher order PT corrections
justifies (a posteriori) the LO order results + the uses of the ambiguous heavy
quark mass to that order. However, our predicted spectra in the range (5173\sim
5226) MeV, summarized in Table 7, for exotic hadrons built with four different
flavours (buds), do not support some previous interpretations of the D0
candidate[1], X(5568), as a pure molecule or a four-quark state. If
experimentally confirmed, it could result from their mixing with an angle: sin
2\theta\approx 0.15. One can also scan the region (2327~ 2444) MeV (where the
D*_{s0}(2317) might be a good candidate) and the one (5173~ 5226) MeV for
detecting these (cuds) and (buds) unmixed exotic hadrons (if any) via,
eventually, their radiative or \pi+hadrons decays.Comment: Version matching with the publised version : some references added
and updated, comments added, misprint corrected (51 pages, 66 figures, 7
tables
Fully and Doubly-heavy four-quarks within QCD Laplace sum rule
We present a review of our results for the masses and couplings of the scalar
fully heavy four-quarks and
tetraquarks states from QCD Laplace sum rule (LSR), their ratios and
double ratio of sum rules (DRSR) within stability criteria and including
Factorized Next-to-Leading Order (FNLO) Perturbative (PT) corrections. As the
Operator Product Expansion (OPE) usually converges for , we
evaluated the QCD spectral functions at Lowest Order of PT QCD and up to
. Our results for the fully heavy four-quark
states may explain the LHCb broad structure around (6.2-6.7)GeV which can be
due to and
molecules or/and their analogue
and tetraquarks. The peak at (6.8-6.9)GeV can be identified to the
molecule or/and the tetraquark state.
Then, combining and DRSR we focus on the analysis of the four-quark
nature of and states. We show that
combining and DRSR can provide more precise results:
MeV and MeV. From our
estimates of the masses of the Pseudoscalar and Vector
states, we observe that the interpolating currents lead to two classes: Class H
(Heavy) states with masses around 6GeV and Class L (Light) states around
(3.8-4.4)GeV where the pseudoscalar (resp. all vector states) are below the
(resp. ) open charm thresholds. Finally, we extend the whole
study to the bottom sector and confront our results with the ones from
different LSR predictions and some other approaches in the literature.Comment: Talk given at the 26th High-Energy Physics international conference
in QCD (10-14 july 2023 Montpellier - France
Local socio-economic effects of protected area conservation: The case of Maromizaha forest, Madagascar
The vision Madagascar Naturally aimed to triple the size of protected areas in Madagascar from 1.7 million hectares to 6 million hectares before 2008, in order to ensure the safe guarding of Madagascar’s natural heritage and the human well-being that depends on it. In 2008, Maromizaha forest was selected by the Ministry of Environment and Forests tobecome a New Protected Area where the delegated manager is the Groupe d’Etude et de Recherche sur les Primates de Madagascar (GERP). One of GERP’s strategies is to provide support to the livelihoods of the local people around the Maromizaha protected area in order to reduce the dependency on natural resources. During April 2014, GERP organized a rapid socio-economic survey of 70 households across six villages, in order to make a preliminary, comparison and assessment of this development support and its impact on the main income generating activities of the local people, their highest level of formal education in 2008 and 2014, and their thinking about conservation offsetting. The results showed that in 2014, 70% of local people were engaged in agriculture and less than 40% in cattle farming. Some villagers have benefited from pilot development projects organized by financial and environmental organizations. Other local people benefited from other livelihood activities related to the conservation management of the forest. Most participants were aware of the ecosystem services of the forests (94.3%) and the education level has increased from 2008 to 2014, although even in 2014, 56% of the survey participants were educated only to primary school level; the rate of illiteracy is at 15.6%. We summarize some strengths, weaknesses and recommendations in order to improve the management of the Maromizaha Protected Area
Evaluation of creep rheological parameters: Indentation versus compressive test
International audienc
Consistency of Published Results on the Pathogen Batrachochytrium dendrobatidis in Madagascar: Formal Comment on Kolby et al. Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Wild Amphibian Populations in Madagascar
判型:B5,平成4年11月30日[目次]バブル消えて思うこと新任教官紹介及び挨拶一番古い新しい大学維管束植物の遺伝子発現機構の解析のための基礎的研究留学感想トピックス学生サークル紹介学生部だより保健管理センターだより卒業生だよりへルン文
1-- and 0++ heavy four-quark and molecule states in QCD
We estimate the masses of the 1^{--} heavy four-quark and molecule states by
combining exponential Laplace (LSR) and finite energy (FESR) sum rules known
perturbatively to lowest order (LO) in alpha_s but including non-perturbative
terms up to the complete dimension-six condensate contributions. This approach
allows to fix more precisely the value of the QCD continuum threshold (often
taken ad hoc) at which the optimal result is extracted.
We use double ratio of sum rules (DRSR) for determining the SU(3) breakings
terms. We also study the effects of the heavy quark mass definitions on these
LO results.
The SU(3) mass-splittings of about (50 - 110) MeV and the ones of about (250
- 300) MeV between the lowest ground states and their 1st radial excitations
are (almost) heavy-flavour independent.
The mass predictions summarized in Table 4 are compared with the ones in the
literature (when available) and with the three Y_c(4260,~4360,~4660) and
Y_b(10890) 1^{--} experimental candidates. We conclude (to this order
approximation) that the lowest observed state cannot be a pure 1^{--}
four-quark nor a pure molecule but may result from their mixings. We extend the
above analyzes to the 0^{++} four-quark and molecule states which are about
(0.5-1) GeV heavier than the corresponding 1^{--} states, while the splittings
between the 0^{++} lowest ground state and the 1st radial excitation is about
(300-500) MeV. We complete the analysis by estimating the decay constants of
the 1^{--} and 0^{++} four-quark states which are tiny and which exhibit a
1/M_Q behaviour.
Our predictions can be further tested using some alternative non-perturbative
approaches or/and at LHCb and some other hadron factories.Comment: 13 pages, 15 figures, 4 tables, version to appear in PLB (more
general choice of the interpolating currents, estimate of the four-quark
meson decay constants, new references added, slight numerical changes for the
0++ mass predictions
The PDF4LHC21 combination of global PDF fits for the LHC Run III
A precise knowledge of the quark and gluon structure of the proton, encoded
by the parton distribution functions (PDFs), is of paramount importance for the
interpretation of high-energy processes at present and future lepton-hadron and
hadron-hadron colliders. Motivated by recent progress in the PDF determinations
carried out by the CT, MSHT, and NNPDF groups, we present an updated
combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo
combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its
Hessian reduction or its replica compression. Extensive benchmark studies are
carried out in order to disentangle the origin of the differences between the
three global PDF sets. In particular, dedicated fits based on almost identical
theory settings and input datasets are performed by the three groups,
highlighting the role played by the respective fitting methodologies. We
compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15,
demonstrating their good overall consistency and a modest reduction of PDF
uncertainties for key LHC processes such as electroweak gauge boson production
and Higgs boson production in gluon fusion. We study the phenomenological
implications of PDF4LHC21 for a representative selection of inclusive,
fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination
is made available via the LHAPDF library and provides a robust, user-friendly,
and efficient method to estimate the PDF uncertainties associated to
theoretical calculations for the upcoming Run III of the LHC and beyond.Comment: 87 pages, 44 figures, 11 table
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