261 research outputs found
Inelastic Dark Matter and the SABRE Experiment
We present here the sensitivity of the SABRE (Sodium iodide with Active
Background REjection) experiment to benchmark proto-philic, spin dependent,
Inelastic Dark Matter models previously proposed due to their lowered tension
with existing experimental results. We perform fits to cross section, mass, and
mass splitting values to find the best fit to DAMA/LIBRA data for these models.
In this analysis, we consider the Standard Halo Model (SHM), as well as an
interesting extension upon it, the SHM+Stream distribution, to investigate the
influence of the Dark Matter velocity distribution upon experimental
sensitivity and whether or not its consideration may be able to help relieve
the present experimental tension. Based on our analysis, SABRE should be
sensitive to all the three benchmark models within 3-5 years of data taking.Comment: Adjusted for full DAMA run 1+2 efficiency. Updated to match published
versio
Setting limits on Effective Field Theories: the case of Dark Matter
The usage of Effective Field Theories (EFT) for LHC new physics searches is
receiving increasing attention. It is thus important to clarify all the aspects
related with the applicability of the EFT formalism in the LHC environment,
where the large available energy can produce reactions that overcome the
maximal range of validity, i.e. the cutoff, of the theory. We show that this
does forbid to set rigorous limits on the EFT parameter space through a
modified version of the ordinary binned likelihood hypothesis test, which we
design and validate. Our limit-setting strategy can be carried on in its
full-fledged form by the LHC experimental collaborations, or performed
externally to the collaborations, through the Simplified Likelihood approach,
by relying on certain approximations. We apply it to the recent CMS mono-jet
analysis and derive limits on a Dark Matter (DM) EFT model. DM is selected as a
case study because the limited reach on the DM production EFT Wilson
coefficient and the structure of the theory suggests that the cutoff might be
dangerously low, well within the LHC reach. However our strategy can also be
applied to EFT's parametrising the indirect effects of heavy new physics in the
Electroweak and Higgs sectors
Deep-sea polychaetes (Annelida) from the Malta Escarpment (western Ionian Sea)
AbstractThe polychaete assemblages from an escarpment area in the western Ionian Sea are characterised in terms of species richness, evenness and trophic composition. Moreover, the first occurrence of the genus Barantolla in the Mediterranean Sea, and of Lumbrinerides carpinei and Exogone (Parexogone) campoyi in Italian waters, is reported. Aricidea trilobata Laubier and Ramos, 1974 is redescribed on the basis of new material with the new name Aricidea (Acmira) jeaneteae, together with a brief description of two deep-water species belonging to the genus Levinsenia
Dissection with harmonic scalpel versus cold instruments in parotid surgery.
The harmonic scalpel (HS) has been used successfully in several head and neck surgical procedures. Some authors highlighted its advantages in reducing operative time, blood loss, and damages to surrounding tissue. In our study, we compared the results obtained during parotidectomy using the HS with the traditional approach to determine the benefits of the HS.130 patients with benign parotid tumors were enrolled and randomized into two groups for this prospective study. 63 patients underwent HS parotidectomy, and 67 patients received a parotidectomy using cold instruments and bipolar electrocautery hemostatic control (CI). 20 HS and 2 CI patients did not meet the inclusion criteria requirements, and were excluded.The admission time was significantly shorter in the HS group than the CI group (3.9 ± 1.2 days and 4.7 ± 1.4 days, respectively, p < 0.01). In the early post-operative period, 84\% of HS patients and 60\% of CI cases showed no facial nerve impairment (p = 0.01). Significantly more CI patients than HS patients showed the onset of Frey's syndrome (29\% and 9\%, respectively, p = 0.01). Multivariate stepwise regression analysis confirmed the reduction in admission length (Odds Ratio (OR): 0.62; p = 0.02) and the lower risk of Frey's syndrome (OR: 0.29; p = 0.04) in HS compared to CI parotidectomies.In parotid surgery, the HS is useful in preventing Frey's syndrome and reducing early transitory facial nerve dysfunction and admission times, and results in decreased medical costs and increased quality of life
First bite syndrome as presenting symptom of parapharyngeal adenoid cystic carcinoma.
First bite syndrome refers to the development of pain in the parotid region after the first bite of each meal.A man was referred to our institution with first bite syndrome as his only symptom. Magnetic resonance imaging of the head and neck revealed a deep lobe parotid mass in close contact with the external carotid artery. Computed tomography guided fine needle biopsy indicated adenoid cystic carcinoma. Total parotidectomy was performed, with en bloc resection of the infiltrated external carotid artery and a selective neck dissection of levels Ib to III. High-weight ion radiotherapy was administered post-operatively.First bite syndrome has hitherto only been described following parapharyngeal space surgery. We present the first case of parotid gland adenoid cystic carcinoma presenting with first bite syndrome as the only symptom. The presence of first bite syndrome should prompt the clinician to investigate the parapharyngeal space and deep lobe of the parotid gland, especially in the absence of other signs or symptoms
On the Validity of the Effective Field Theory for Dark Matter Searches at the LHC Part III: Analysis for the t-channel
We extend our recent analysis of the limitations of the effective field theory approach to studying dark matter at the LHC, by investigating the case in which Dirac dark matter couples to standard model quarks via t-channel exchange of a heavy scalar mediator. We provide analytical results for the validity of the effective field theory description, for both 1as = 8 TeV and 14 TeV. We make use of a MonteCarlo event generator to assess the validity of our analytical conclusions. We also point out the general trend that in the regions where the effective field theory is valid, the dark matter relic abundance is typically large
Evaporation and scattering of momentum- and velocity-dependent dark matter in the Sun
Dark matter with momentum- or velocity-dependent interactions with nuclei has shown significant promise for explaining the so-called Solar Abundance Problem, a longstanding discrepancy between solar spectroscopy and helioseismology. The best-fit models are all rather light, typically with masses in the range of 3–5 GeV. This is exactly the mass range where dark matter evaporation from the Sun can be important, but to date no detailed calculation of the evaporation of such models has been performed. Here we carry out this calculation, for the first time including arbitrary velocity- and momentum-dependent interactions, thermal effects, and a completely general treatment valid from the optically thin limit all the way through to the optically thick regime. We find that depending on the dark matter mass, interaction strength and type, the mass below which evaporation is relevant can vary from 1 to 4 GeV. This has the effect of weakening some of the better-fitting solutions to the Solar Abundance Problem, but also improving a number of others. As a by-product, we also provide an improved derivation of the capture rate that takes into account thermal and optical depth effects, allowing the standard result to be smoothly matched to the well-known saturation limit
The absolute age of the globular cluster M15 using near-infrared adaptive optics images from PISCES/LBT
We present deep near-infrared (NIR) J, Ks photometry of the old, metal-poor
Galactic globular cluster M\,15 obtained with images collected with the LUCI1
and PISCES cameras available at the Large Binocular Telescope (LBT). We show
how the use of First Light Adaptive Optics system coupled with the (FLAO)
PISCES camera allows us to improve the limiting magnitude by ~2 mag in Ks. By
analyzing archival HST data, we demonstrate that the quality of the LBT/PISCES
color magnitude diagram is fully comparable with analogous space-based data.
The smaller field of view is balanced by the shorter exposure time required to
reach a similar photometric limit. We investigated the absolute age of M\,15 by
means of two methods: i) by determining the age from the position of the main
sequence turn-off; and ii) by the magnitude difference between the MSTO and the
well-defined knee detected along the faint portion of the MS. We derive
consistent values of the absolute age of M15, that is 12.9+-2.6 Gyr and
13.3+-1.1 Gyr, respectively.Comment: 13 pages, 8 figures, ApJ accepte
LHC phenomenology of dark matter with a color-octet partner
Colored dark sectors where the dark matter particle is accompanied by colored partners have recently attracted theoretical and phenomenological interest. We explore the possibility that the dark sector consists of the dark matter particle and a color-octet partner, where the interaction with the Standard Model is governed by an effective operator involving gluons. The resulting interactions resemble the color analogues of electric and magnetic dipole moments. Although many phenomenological features of this kind of model only depend on the group representation of the partner under SU(3)c, we point out that interesting collider signatures such as R-hadrons are indeed controlled by the interaction operator between the dark and visible sector. We perform a study of the current constraints and future reach of LHC searches, where the complementarity between different possible signals is highlighted and exploited
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