A
bstract
We consider an axion-like particle (ALP) coupled to Standard Model (SM) fermions as a mediator between the SM and a fermionic dark matter (DM) particle. We explore the case where the ALP-SM ...and/or the ALP-DM couplings are too small to allow for DM generation via standard freeze-out. DM is therefore thermally decoupled from the visible sector and must be generated through either freeze-in or decoupled freeze-out (DFO). In the DFO regime, we present an improved approach to obtain the relic density by solving a set of three stiff coupled Boltzmann equations, one of which describes the energy transfer from the SM to the dark sector. Having determined the region of parameter space where the correct relic density is obtained, we revisit experimental constraints from electron beam dump experiments, rare
B
and
K
decays, exotic Higgs decays at the LHC, astrophysics, dark matter searches and cosmology. In particular, for our specific ALP scenario we (re) calculate and improve beam dump, flavour and supernova constraints. Throughout our calculation we implement state-of-the-art chiral perturbation theory results for the ALP partial decay width to hadrons. We find that while the DFO region, which predicts extremely small ALP-fermion couplings, can probably only be constrained by cosmological observables, the freeze-in region covers a wide area of parameter space that may be accessible to other more direct probes. Some of this parameter space is already excluded, but a significant part should be accessible to future collider experiments.
A
bstract
The relic density of TeV-scale wino-like neutralino dark matter in the MSSM is subject to potentially large corrections as a result of the Sommerfeld effect. A recently developed framework ...enables us to calculate the Sommerfeld-enhanced relic density in general MSSM scenarios, properly treating mixed states and multiple co-annihilating channels as well as including off-diagonal contributions. Using this framework, including on-shell one-loop mass splittings and running couplings and taking into account the latest experimental constraints, we perform a thorough study of the regions of parameter space surrounding the well known pure-wino scenario: namely the effect of sfermion masses being non-decoupled and of allowing non-negligible Higgsino or bino components in the lightest neutralino. We further perform an investigation into the effect of thermal corrections and show that these can safely be neglected. The results reveal a number of phenomenologically interesting but so far unexplored regions where the Sommerfeld effect is sizeable. We find, in particular, that the relic density can agree with experiment for dominantly wino neutralino dark matter with masses ranging from 1.7 to beyond 4 TeV. In light of these results the bounds from Indirect Detection on wino-like dark matter should be revisited.
Next-to-minimal dark matter at the LHC Bharucha, A.; Brümmer, F.; Desai, N.
The journal of high energy physics,
11/2018, Letnik:
2018, Številka:
11
Journal Article
Recenzirano
Odprti dostop
A
bstract
We examine the collider signatures of a WIMP dark matter scenario comprising a singlet fermion and an SU(2)
n
-plet fermion, with a focus on
n
= 3 and
n
= 5. The singlet and
n
-plet masses ...are of the order of the electroweak scale. The
n
-plet contains new charged particles which will be copiously pair-produced at the LHC. Small mixing angles and near-degenerate masses, both of which feature naturally in these models, give rise to long-lived particles and their characteristic collider signatures. In particular, the
n
= 5 model can be constrained by displaced lepton searches independently of the mixing angle, generically ruling out 5-plet masses below about 280 GeV. For small mixing angles, we show that there is a parameter range for which the model reproduces the observed thermal relic density but is severely constrained by disappearing track searches in both the
n
= 3 and the
n
= 5 cases. The
n
= 3 model is further constrained by soft di-lepton searches irrespective of whether any of the new particles are long-lived.
High amplitude propagated contractions Bharucha, A. E.
Neurogastroenterology & motility/Neurogastroenterology and motility,
November 2012, Letnik:
24, Številka:
11
Journal Article
Recenzirano
Odprti dostop
While most colonic motor activity is segmental and non‐propulsive, colonic high amplitude propagated contractions (HAPC) can transfer colonic contents over long distances and often precede ...defecation. High amplitude propagated contractions occur spontaneously, in response to pharmacological agents or colonic distention. A subset of patients with slow transit constipation have fewer HAPC. In this issue of Neurogastroenterology and Motility, Rodriguez et al. report that anal relaxation during spontaneous and bisacodyl‐induced HAPC exceeds anal relaxation during rectal distention in constipated children undergoing colonic manometry. Moreover, and consistent with a neural mechanism, anal relaxation often precedes arrival of HAPC in the left colon. High amplitude propagated contractions are also used to evaluate the motor response to a meal and pharmacological stimuli (e.g., bisacodyl, neostigmine) and to identify colonic inertia during colonic motility testing in chronic constipation. This editorial comprehensively reviews the characteristics, physiology and pharmacology of HAPC, their assessment by manometry, and relevance to constipation and diarrhea.
Parkinson disease (PD) may affect the autonomic nervous system and may cause constipation; however, few studies have explored constipation preceding the motor onset of PD. We investigated ...constipation preceding PD using a case-control study design in a population-based sample.
Using the medical records-linkage system of the Rochester Epidemiology Project, we identified 196 subjects who developed PD in Olmsted County, MN, from 1976 through 1995. Each incident case was matched by age (+/-1 year) and sex to a general population control. We reviewed the complete medical records of cases and controls in the medical records-linkage system to ascertain the occurrence of constipation preceding the onset of PD (or index year).
Constipation preceding PD or the index year was more common in cases than in controls (odds ratio OR 2.48; 95% confidence interval CI 1.49 to 4.11; p = 0.0005). This association remained significant after adjusting for smoking and coffee consumption (ever vs never), and after excluding constipation possibly induced by drugs. In addition, the association remained significant in analyses restricted to constipation documented 20 or more years before the onset of motor symptoms of PD. Although the association was stronger in women than in men and in patients with PD with rest tremor compared with patients with PD without rest tremor, these differences were not significant.
Our findings suggest that constipation occurring as early as 20 or more years before the onset of motor symptoms is associated with an increased risk of Parkinson disease.
Background
Anorectal disorders such as dyssynergic defecation, fecal incontinence, levator ani syndrome, and solitary rectal ulcer syndrome are common, and affect both the adult and pediatric ...populations. Although they are treated with several treatment approaches, over the last two decades, biofeedback therapy using visual and verbal feedback techniques has emerged as an useful option. Because it is safe, it is commonly recommended. However, the clinical efficacy of biofeedback therapy in adults and children is not clearly known, and there is a lack of critical appraisal of the techniques used and the outcomes of biofeedback therapy for these disorders.
Purpose
The American Neurogastroenterology and Motility Society and the European Society of Neurogastroenterology and Motility convened a task force to examine the indications, study performance characteristics, methodologies used, and the efficacy of biofeedback therapy, and to provide evidence‐based recommendations. Based on the strength of evidence, biofeedback therapy is recommended for the short‐term and long‐term treatment of constipation with dyssynergic defecation (Level I, Grade A), and for the treatment of fecal incontinence (Level II, Grade B). Biofeedback therapy may be useful in the short‐term treatment of Levator Ani Syndrome with dyssynergic defecation (Level II, Grade B), and solitary rectal ulcer syndrome with dyssynergic defecation (Level III, Grade C), but the evidence is fair. Evidence does not support the use of biofeedback for the treatment of childhood constipation (Level 1, Grade D).
Anorectal disorders such as dyssynergic defecation, fecal incontinence, levator ani syndrome, and solitary rectal ulcer syndrome are common, and affect both the adult and pediatric populations.
Introduced approximately 10 years ago, high‐resolution manometry catheters have fostered interest in anorectal manometry. This review, which accompanies two articles in this issue of ...Neurogastroenterology and Motility, reviews the methods, clinical indications, utility, and pitfalls of anorectal manometry and revisits the American Gastroenterological Association (AGA) Medical Position Statement on Anorectal Testing Techniques, which was last published in 1999. High‐resolution manometry provides a refined assessment of the anorectal pressure profile, obviates the need for station pull‐through maneuvers, and minimizes movement artifacts. In selected cases, this refined assessment may be useful for identifying structural abnormalities or anal weakness. However, many manometry patterns that were previously regarded as abnormal are also observed in a majority of healthy patients, which substantially limits the utility of manometry for identifying defecatory disorders. It is our impression that most conclusions of the AGA medical position statement from 1999 remain valid today. High‐resolution techniques have not substantially affected the number of publications on or management of anorectal disorders. The ongoing efforts of an international working group to standardize techniques for anorectal manometry are welcome. Although high‐resolution manometry is more than an expensive hobby, improvements in catheter design and further research to rigorously define and evaluate these techniques are necessary to determine if they are worth every penny.
High‐resolution manometry (HRM) catheters provide better spatial resolution of anorectal pressures than standard (non‐HRM catheters) and minimize movement artifacts during manometry. However, with a few exceptions, HRM catheters have not increased the clinical utility of manometry to quantify anal weakness. By contrast to the esophagus, the number of publications related to anorectal manometry has not substantially increased after the introduction of HRM. Further studies are necessary, in particular to improve the currently limited utility of HRM for diagnosing defecatory disorders.
Challenges in semileptonic B decays Gambino, P.; Kronfeld, A. S.; Rotondo, M. ...
The European physical journal. C, Particles and fields,
10/2020, Letnik:
80, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Two of the elements of the Cabibbo–Kobayashi–Maskawa quark mixing matrix,
|
V
ub
|
and
|
V
cb
|
, are extracted from semileptonic
B
decays. The results of the
B
factories, analysed in the light of ...the most recent theoretical calculations, remain puzzling, because for both
|
V
ub
|
and
|
V
cb
|
the exclusive and inclusive determinations are in clear tension. Further, measurements in the
τ
channels at Belle, Babar, and LHCb show discrepancies with the Standard Model predictions, pointing to a possible violation of lepton flavor universality. LHCb and Belle II have the potential to resolve these issues in the next few years. This article summarizes the discussions and results obtained at the MITP workshop held on April 9–13, 2018, in Mainz, Germany, with the goal to develop a medium-term strategy of analyses and calculations aimed at solving the puzzles. Lattice and continuum theorists working together with experimentalists have discussed how to reshape the semileptonic analyses in view of the much higher luminosity expected at Belle II, searching for ways to systematically validate the theoretical predictions in both exclusive and inclusive
B
decays, and to exploit the rich possibilities at LHCb.
A
bstract
We delineate the allowed parameter and mass range for a wino-like dark matter particle containing some Higgsino admixture in the MSSM by analysing the constraints from diffuse gamma-rays ...from the dwarf spheroidal galaxies, galactic cosmic rays, direct detection and cosmic microwave background anisotropies. A complete calculation of the Sommerfeld effect for the mixed-neutralino case is performed. We find that the combination of direct and indirect searches poses significant restrictions on the thermally produced wino-Higgsino dark matter with correct relic density. For
μ >
0 nearly the entire parameter space considered is excluded, while for
μ <
0 a substantial region is still allowed, provided conservative assumptions on astrophysical uncertainties are adopted.
Pelvic floor: anatomy and function Bharucha, A. E.
Neurogastroenterology and motility,
July 2006, Letnik:
18, Številka:
7
Journal Article
Recenzirano
The pelvic floor is a dome‐shaped striated muscular sheet that encloses the bladder, uterus, and rectum, and, together with the anal sphincters, has an important role in regulating storage and ...evacuation of urine and stool. This article reviews the anatomy, nerve supply, pharmacology, and functions of the anal sphincters and the pelvic floor. The internal and external anal sphincters are primarily responsible for maintaining faecal continence at rest and when continence is threatened, respectively. Defecation is a somato‐visceral reflex regulated by dual nerve supply (i.e. somatic and autonomic) to the anorectum. The net effects of sympathetic and cholinergic stimulation are to increase and reduce anal resting pressure, respectively. Faecal incontinence and functional defecatory disorders may result from structural changes and/or functional disturbances in the mechanisms of faecal continence and defecation.
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