1,075 research outputs found
A Strong Sector at the LHC: Top Partners in Same-Sign Dileptons
Heavy partners of the top quark are a common prediction of many models in
which a new strongly-coupled sector is responsible for the breaking of the EW
symmetry. In this paper we investigate their experimental signature at the LHC,
focusing on the particularly clean channel of same-sign dileptons.
We show that, thank to a strong interaction with the top quark which allows
them to be singly produced at a sizable rate, the top partners will be
discovered at the LHC if their mass is below 1.5 TeV, higher masses being
possible in particularly favorable (but plausible) situations. Being the
partners expected to be lighter in both the Higgsless and Composite-Higgs
scenarios, the one of same-sign dileptons is found to be a very promising
channel in which these models could be tested.
We also discuss several experimental signatures which would allow, after the
discovery of the excess, to uniquely attribute it to the top partners
production and to measure the relevant physical parameters, i.e. the top
partners masses and couplings. We believe that our results constitute a valid
starting point for a more detailed experimental study.Comment: Corrected some typos, added a reference, 23 page
The Other Natural Two Higgs Doublet Model
We characterize models where electroweak symmetry breaking is driven by two
light Higgs doublets arising as pseudo-Nambu-Goldstone bosons of new dynamics
above the weak scale. They represent the simplest natural two Higgs doublet
alternative to supersymmetry. We construct their low-energy effective
Lagrangian making only few specific assumptions about the strong sector. These
concern their global symmetries, their patterns of spontaneous breaking and the
sources of explicit breaking. In particular we assume that all the explicit
breaking is associated with the couplings of the strong sector to the Standard
Model fields, that is gauge and (proto)-Yukawa interactions. Under those
assumptions the scalar potential is determined at lowest order by very few free
parameters associated to the top sector. Another crucial property of our
scenarios is the presence of a discrete symmetry, in addition to custodial
SO(4), that controls the -parameter. That can either be simple CP or a
that distinguishes the two Higgs doublets. Among various possibilities we study
in detail models based on SO(6)/SO(4) SO(2), focussing on their
predictions for the structure of the scalar spectrum and the deviations of
their couplings from those of a generic renormalizable two Higgs doublet model.Comment: 54 page
Unveiling the intruder deformed 0 state in Si
The 0 state in Si has been populated at the {\sc Ganil/Lise3}
facility through the -decay of a newly discovered 1 isomer in
Al of 26(1) ms half-life. The simultaneous detection of pairs
allowed the determination of the excitation energy E(0)=2719(3) keV and
the half-life T=19.4(7) ns, from which an electric monopole strength of
(E0)=13.0(0.9) was deduced. The 2 state is
observed to decay both to the 0 ground state and to the newly observed
0 state (via a 607(2) keV transition) with a ratio
R(2)=1380(717). Gathering all
information, a weak mixing with the 0 and a large deformation parameter
of =0.29(4) are found for the 0 state, in good agreement with
shell model calculations using a new {\sc sdpf-u-mix} interaction allowing
\textit{np-nh} excitations across the N=20 shell gap.Comment: 5 pages, 3 figures, accepted for publication in Physical Review
Letter
Aspects of acceptance: building a shared conceptual understanding
Many contemplatives, scientists, and clinicians have pointed to the value of responding to life’s difficulties by accepting experiences as they are. A growing body of research also suggests that acceptance contributes to effective coping with adversity, reduced stress, and improved emotional well-being. Yet within the scientific literature, there is little consensus on what acceptance means or how it should be measured. This makes it nearly impossible to synthesize empirical work on acceptance into a cohesive scientific understanding. Our goal in this paper is to clarify four facets of acceptance that are commonly referenced in research: acknowledging, allowing, non-judging, and non-attachment. We do not propose a specific definition of acceptance or even a set of privileged facets that must be included in future frameworks. We instead offer a vocabulary to facilitate productive communication among researchers that will, in turn, enable a more definitive scientific understanding of this important construct to emerge. After defining and explaining these aspects of acceptance, we further clarify these constructs in two ways. First, we illustrate how the four aspects are dissociable from one another. Second, we analyze their correspondence to related constructs from Acceptance and Commitment Therapy (ACT). Finally, we provide a concept worksheet that scholars can utilize to precisely operationalize acceptance in their own work
Clinical and service implications of a cognitive analytic therapy model of psychosis
Cognitive analytic therapy (CAT) is an integrative, interpersonal model of therapy predicated on a radically social concept of self, developed over recent years in the UK by Anthony Ryle. A CAT-based model of psychotic disorder has been developed much more recently based on encouraging early experience in this area. The model describes and accounts for many psychotic experiences and symptoms in terms of distorted, amplified or muddled enactments of normal or ‘neurotic’ reciprocal role procedures (RRPs) and of damage at a meta-procedural level to the structures of the self.
Reciprocal role procedures are understood in CAT to represent the outcome of the process of internalization of early, sign-mediated, interpersonal experience and to constitute the basis for all mental activity, normal or otherwise. Enactments of maladaptive RRPs generated by early interpersonal stress are seen in this model to constitute a form of ‘internal expressed emotion’. Joint description of these RRPs and their enactments (both internally and externally) and their subsequent revision is central to the practice of CAT during which they are mapped out through written and diagrammatic reformulations.
This model may usefully complement and extend existing approaches, notably recent CBT-based interventions, particularly with ‘difficult’ patients, and generate meaningful and helpful understandings of these disorders for both patients and their treating teams. We suggest that use of a coherent and robust model such as CAT could have important clinical and service implications in terms of developing and researching models of these disorders as well as for the training of multidisciplinary teams in their effective treatment
Prolate-Spherical Shape Coexistence at N=28 in S
The structure of S has been studied using delayed and
electron spectroscopy at \textsc{ganil}. The decay rates of the 0
isomeric state to the 2 and 0 states have been measured for the
first time, leading to a reduced transition probability
B(E2~:~20= 8.4(26)~efm and a monopole
strength (E0~:~00
=~8.7(7)10. Comparisons to shell model calculations point
towards prolate-spherical shape coexistence and a phenomenological two level
mixing model is used to extract a weak mixing between the two configurations.Comment: 5 pages, 3 figures, accepted for publication in Physical Review
Letter
A new cross section measurement of reactions induced by 3He-particles on a carbon target
International audienceThe production of intense beams of light radioactive nuclei can be achieved at the SPIRAL2 facility using intense stable beams accelerated by the driver accelerator and impinging on light targets. The isotope 14O is identied to be of high interest for future experiments. The excitation function of the production reaction 12C(3He, n)14O was measured between 7 and 35 MeV. Results are compared with literature data. As an additional result, we report the rst cross-section measurement for the 12C(3He, +n)10C reaction. Based on this new result, the potential in-target 14O yield at SPIRAL2 was estimated: 2.4x1011 pps, for 1 mA of 3He at 35 MeV. This is a factor 140 higher than the in-target yield at SPIRAL1
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