A
bstract
Anomalous interactions involving the top quark contribute to some of the most difficult observables to directly access experimentally. They can give however a sizeable correction to very ...precisely measured observables at the loop level. Using a model-independent effective Lagrangian approach, we present the leading indirect constraints on dimension-six effective operators involving the top quark from electroweak precision data. They represent the most stringent constraints on these interactions, some of which may be directly testable in future colliders.
A
bstract
We classify all possible new scalar particles that can have renormalizable linear couplings to Standard Model fields and therefore be singly produced at colliders. We show that this ...classification exhausts the list of heavy scalar particles that contribute at the tree level to the Standard Model effective Lagrangian to dimension six. We compute this effective Lagrangian for a general scenario with an arbitrary number of new scalar particles and obtain flavor-preserving constraints on their couplings and masses. This completes the tree-level matching of the coefficients of dimension five and six operators in the effective Lagrangian to arbitrary extensions of the Standard Model.
A light sneutrino rescues the light stop Chala, M.; Delgado, A.; Nardini, G. ...
The journal of high energy physics,
04/2017, Letnik:
2017, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A
bstract
Stop searches in supersymmetric frameworks with
R
-parity conservation usually assume the lightest neutralino to be the lightest supersymmetric particle. In this paper we consider an ...alternative scenario in which the left-handed tau sneutrino is lighter than neutralinos and stable at collider scales, but possibly unstable at cosmological scales. Moreover the (mostly right-handed) stop
t
∼
is lighter than all electroweakinos, and heavier than the scalars of the third generation lepton doublet, whose charged component,
τ
∼
, is heavier than the neutral one,
ν
∼
. The remaining supersymmetric particles are decoupled from the stop phenomenology. In most of the parameter space, the relevant stop decays are only into
t
τ
∼
τ
,
t
ν
∼
ν
and
b
ν
∼
τ
via off-shell electroweakinos. We constrain the branching ratios of these decays by recasting the most sensitive stop searches. Due to the “double invisible” kinematics of the
t
∼
→
t
ν
∼
ν
process, and the low efficiency in tagging the
t
τ
∼
τ
decay products, light stops are generically allowed. In the minimal supersymmetric standard model with ∼ 100 GeV sneutrinos, stops with masses as small as ∼ 350 GeV turn out to be allowed at 95% CL.
We calculate the renormalisation group running of the bosonic Standard Model (SM) effective operators at one loop and to order
v
4
/
Λ
4
, with
v
∼
246
GeV being the electroweak scale and
Λ
the ...unknown new physics threshold. We focus on contributions driven by one dimension-eight term and SM couplings, thus extending (and completing) the effort initiated in Chala et al. (SciPost Phys 11:065, 2021).
arXiv:2106.05291
, in which quantum corrections from pairs of dimension-six interactions were considered. We highlight some interesting consequences, including the renormalisation of loop-induced interactions by tree-level generated terms and, more importantly, the validity of positivity bounds on different operators inducing anomalous gauge quartic couplings.
Target thermal capabilities are one of the major key points for CANS (Compact Accelerator-based Neutron Source) developments. Indeed, high energy (few MeV) and high average current (few tens of mA) ...proton or deuteron beams are required to produce high thermal neutron flux of 101³ n.cm⁻2.s⁻1 or greater. The targets must therefore absorb and dissipate a high thermal power. In order to make progress on their designs without deuteron or proton beams, we developed a compact electron beamline based on an Electron Cyclotron Resonance (ECR) source that permits testing of targets under relevant thermal conditions at power densities up 3 kW. cm⁻2.
Bats have been implicated as reservoirs of relapsing fever group spirochaetes since the beginning of the last century. Recently, bat‐associated spirochaetes have been reported as human pathogens. In ...1968, a spirochaete was detected in blood of the bat Natalus tumidirostris captured inside the Macaregua cave, Colombia. Data on this microorganism were never published again. The aim of this study was to evaluate the presence of Borrelia DNA in blood from bats of Macaregua cave. We performed molecular analyses using a genus‐specific real‐time PCR targeting the 16S rRNA to detect DNA of Borrelia in blood samples from 46 bats captured in the Macaregua cave. Positive samples were submitted to a battery of PCRs aiming to amply Borrelia 16S rRNA, flaB, glpQ, p66, ospC, clpA, clpX, nifS, pepX, pyrG, recG, rplB and uvrA genes. Seventeen samples were positive for Borrelia after real‐time PCR. With the exception of flaB gene, attempts to amplify further loci were unsuccessful. Nucleotide and amino acid divergences of four flaB haplotypes characterized from blood of Carollia perspicillata showed Borrelia burgdorferi sensu lato (Bbsl) as the most closely related group. A phylogenetic tree including 74 sequences of the genus confirmed this trend, since Borrelia genotypes detected in bats from Macaregua formed a monophyletic group basally positioned to Bbsl. Our results suggest that Borrelia genotypes characterized from bats roosting in the Macaregua cave might constitute a new taxon within the genus. This is the first molecular characterization of a Borrelia sp. in Colombia.
A gluon resonance
G of mass below 1 TeV could be the origin of the
t
t
¯
forward–backward asymmetry observed at the Tevatron provided that new decay modes
G
→
q
Q
¯
, with
q a standard quark and
Q ...its massive excitation, make
G broad enough. We consider all the different cases, with
q the top, the bottom or a light quark and dominant decay modes
Q
→
W
q
′
or
Q
→
Z
q
. We show that current experimental searches are unable to probe the model, but that minimal departures from these analyses can explore a large region of its parameter space for the current LHC luminosity. This includes the challenging case with the new quarks decaying mostly into light quark flavors. In some channels not only the heavy quark but also the massive gluon can be reconstructed, which would stablish the origin of the
t
t
¯
asymmetry. Similar analyses can be applied to more general models with new massive gluons and vectorlike quarks.
Abstract
The full-scale invasion of Ukraine by Russian military forces on 24 February 2022 put the radiological well-being of the people in Ukraine under unprecedented threat. Apart from the risks ...linked to operating nuclear power plants, there was substantial evidence of looting of facilities of all kinds, including those holding radioactive materials, as well as the scope for physical disturbance of radioactively contaminated areas and waste storage facilities. The actions of Russian military personnel invading Ukraine through the territory of the Chornobyl Exclusion Zone (the ChEZ) were of serious concern. Before its shutdown a few days after the beginning of the occupation, the automated radiation monitoring system of the ChEZ recorded sharp increases in the gamma-background in several areas which indicated some non-typical processes taking place on its territory. The State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) and its technical support organisation, the Scientific and Technical Centre for Nuclear and Radiation Safety (SSTC NRS), as well as the rest of the professional nuclear community in Ukraine and worldwide, recognised the potential for movement of the radioactive contamination (reaching 10
1
–10
4
kBq m
−2
Cs-137 in the most of the territory) by the Russian military machinery and personnel to areas outside the ChEZ, creating locally contaminated spots along the routes taken by the invaders towards Kyiv. Certain apprehensions were caused by the inventory carried out after the liberation of the ChEZ which revealed the theft of calibration sources and radioactive samples from laboratories located in Chornobyl. As soon as this information became available to the public, it caused a wide response and anxiety, as a result of which SNRIU made a decision to conduct a radiation survey of the liberated territories in the Kyiv region. The survey was conducted between June and December 2022 by SSTC NRS specialists with the support of DSA. The scope of the survey was limited by available time and resources; however, the total route of the survey was about 840 km, and covered more than 50 settlements and a limited part of the ChEZ. The radiation survey combined the continuous gamma-dose rate measurements by the detectors installed in the laboratory vehicle and additional manual measurements at specified points. As a result of the radiation survey, no deterioration of the radiation situation was observed in the liberated territories. No contaminated objects, radiation sources, or other radioactive material removed from the ChEZ were found either. Measurements of the Cs-137 soil contamination in the ChEZ, although limited, corresponded to the results which had been obtained before the war. It can be concluded that in the surveyed territories, the direct impact on the public in the form of additional radioactive contamination removed from the ChEZ in February-March 2022 was negligible. The same applies to the radiation consequences of forest fires that occurred in the ChEZ during its occupation. However, due to the damage of the radiation monitoring system, explosive hazard, and destruction of transport infrastructure, the consequences of the occupation of the ChEZ by Russian troops will be long-term.
Leptospirosis is caused by pathogenic Leptospira spp., which can be found in nature among domestic and wild animals. In Colombia, the Macaregua cave is known for its bat richness; thus, because bats ...are reservoir hosts of human microbiological pathogens, we determined if the Macaregua cave bats harbored Leptospira in the wild. A total of 85 kidney samples were collected from three bat species (Carollia perspicillata, Mormoops megalophylla, and Natalus tumidirostris) to detect Leptospira spp. The 16S rRNA gene was targeted through conventional PCR and qPCR; in addition, the LipL32 gene was detected using conventional PCR. Obtained amplicons were purified and sequenced for phylogenetic analysis. The Leptospira spp. 16S rRNA gene was detected in 51.8% bat kidneys, of which 35 sequences were obtained, all clustering within the pathogenic group. Moreover, 11 sequences presented high-identity-values with Leptospiranoguchii, Leptospiraalexanderi, Leptospiraborgpetersenii, Leptospirakirschneri, and Leptospiramayottensis. From the 16S rRNALeptospira spp.-positive population samples, 28 amplified for the LipL32 gene, and 23 sequences clustered in five different phylogenetic groups. In conclusion, we detected the circulation of different groups of Leptospira spp. sequences among cave bats in the wild; some sequences were detected in more than one bat specimen from the same species, suggesting a conspecific transmission within the cave.
People with chronic low back pain experience myriads of problems from living with their condition. This study aimed to explore the lived experience of people with chronic low back pain in Ethiopia.
...This is a qualitative semi-structured study design which used an interpretative phenomenological analysis approach for data analysis.
Fifteen adults (10 women and 5 men) with chronic low back pain (duration ≥ 3 months) with age ranging from 19 to 66 years old were interviewed.
Participants were recruited from the outpatient departments of the University of Gondar hospital in Gondar, Ethiopia.
Data was collected through an in-depth semi-structured interview. Interviews were audio-recorded and transcribed verbatim. Data were analyzed through an iterative process, beginning with a line-by-line coding to identify the lived experience of chronic low back pain.
Five main themes related to the lived experience of people with chronic low back pain emerged: 1) CLBP impacts life on a day-to-day basis, 2) The invisibility of pain results in misunderstanding, misjudgment, and loneliness, 3) The cause of pain is a mystery, 4) The search for the cure is a quest, 5) Each person has their ways of managing, coping, and living with pain.
The findings from this study improve our understanding of the experience of people with chronic low back pain and its impact on their day-to-day life in Ethiopia. The findings from this study could inform the development of culturally centered chronic low back pain interventions such as self-management programs in the Ethiopian context.
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