scholarly journals Dark scalars and heavy neutral leptons at DarkQuest

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Brian Batell ◽  
Jared A. Evans ◽  
Stefania Gori ◽  
Mudit Rai

Abstract The proposed DarkQuest beam dump experiment, a modest upgrade to the existing SeaQuest/SpinQuest experiment, has great potential for uncovering new physics within a dark sector. We explore both the near-term and long-term prospects for observing two distinct, highly-motivated hidden sector benchmark models: heavy neutral leptons and Higgs-mixed scalars. We comprehensively examine the particle production and detector acceptance at DarkQuest, including an updated treatment of meson production, and light scalar production through both bremsstrahlung and gluon-gluon fusion. In both benchmark models, DarkQuest will provide an opportunity to probe previously inaccessible interesting regions of parameter space on a fairly short timescale when compared to other proposed experiments.

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Yong Du ◽  
Fei Huang ◽  
Hao-Lin Li ◽  
Jiang-Hao Yu

Abstract We investigate a simplified freeze-in dark-matter model in which the dark matter only interacts with the standard-model neutrinos via a light scalar. The extremely small coupling for the freeze-in mechanism is naturally realized in several neutrino-portal scenarios with the secret neutrino interactions. We study possible evolution history of the hidden sector: the dark sector would undergo pure freeze-in production if the interactions between the dark-sector particles are negligible, while thermal equilibrium within the dark sector could occur if the reannihilation of the dark matter and the scalar mediator is rapid enough. We investigate the relic abundance in the freeze-in and dark freeze-out regimes, calculate evolution of the dark temperature, and study its phenomenological aspects on BBN and CMB constraints, the indirect-detection signature, as well as the potential to solve the small scale structure problem.


Open Physics ◽  
2016 ◽  
Vol 14 (1) ◽  
pp. 281-303 ◽  
Author(s):  
Maksym Deliyergiyev

AbstractMany difficulties are encountered when attempting to pinpoint a common origin for several observed astrophysical anomalies, and when assessing their tension with existing exclusion limits. These include systematic uncertainties affecting the operation of the detectors, our knowledge of their response, astrophysical uncertainties, and the broad range of particle couplings that can mediate interaction with a detector target. Particularly interesting astrophysical evidence has motivated a search for dark-photon, and focused our attention on a Hidden Valleys model with a GeV-scale dark sector that produces exciting signatures. Results from recent underground experiments are also considered.There is a ‘light’ hidden sector (dark sector), present in many models of new physics beyond the Standard Model, which contains a colorful spectrum of new particles. Recently, it has been shown that this spectrum can give rise to unique signatures at colliders when the mass scale in the hidden sector is well below a TeV; as in Hidden Valleys, Stueckelberg extensions, and Unparticle models. These physics models produce unique signatures of collimated leptons at high energies. By studying these ephemeral particles we hope to trace the history of the Universe. Our present theories lead us to believe that there is something new just around the corner, which should be accessible at the energies made available by modern colliders.


Author(s):  
Omar Hashim Thanon

Since peaceful coexistence reflects in its various aspects the concept of harmony between the members of the same society with their different national, religious and sectarian affiliations, as well as their attitudes and ideas, what brings together these are the common bonds such as land, interests and common destiny. But this coexistence is exposing for crises and instability and the theft of rights and other that destroy the communities with their different religious, national, sectarian, ethnic aspects, especially if these led to a crisis of fighting or war, which produces only destruction and mass displacement, ttherefore, the process of bridging the gap between the different parts of society in the post-war phase through a set of requirements that serve as the basis for the promotion of peaceful coexistence within the same country to consolidate civil and community peace in order to create a general framework and a coherent basis to reconstruct the community again.      Hence the premise of the research by asking about the extent of the possibility and ability of the community of religious and ethnic diversity, which has been exposed to these crises, which aimed at this diversity, basically to be able to rise and re-integrate within the same country and thus achieve civil and community peace, and Mosul is an example for that, the negative effects of the war and the accomplices of many criminal acts have given rise to hatred and fear for all, leading to the loss of livelihoods, which in the long term may have devastating social and psychological consequences.        To clarify all of this, the title of the first topic was a review of the concept and origin of peaceful coexistence. While the second topic dealt with the requirements of peaceful coexistence and social integration in Mosul, the last topic has identified the most important challenges facing the processes of coexistence and integration in Mosul. All this in order to paint a better future for the conductor at all levels in the near term at the very least to achieve the values of this peaceful coexistence, especially in the post-war period.


Philosophies ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Nadisha-Marie Aliman ◽  
Leon Kester ◽  
Roman Yampolskiy

In the last years, artificial intelligence (AI) safety gained international recognition in the light of heterogeneous safety-critical and ethical issues that risk overshadowing the broad beneficial impacts of AI. In this context, the implementation of AI observatory endeavors represents one key research direction. This paper motivates the need for an inherently transdisciplinary AI observatory approach integrating diverse retrospective and counterfactual views. We delineate aims and limitations while providing hands-on-advice utilizing concrete practical examples. Distinguishing between unintentionally and intentionally triggered AI risks with diverse socio-psycho-technological impacts, we exemplify a retrospective descriptive analysis followed by a retrospective counterfactual risk analysis. Building on these AI observatory tools, we present near-term transdisciplinary guidelines for AI safety. As further contribution, we discuss differentiated and tailored long-term directions through the lens of two disparate modern AI safety paradigms. For simplicity, we refer to these two different paradigms with the terms artificial stupidity (AS) and eternal creativity (EC) respectively. While both AS and EC acknowledge the need for a hybrid cognitive-affective approach to AI safety and overlap with regard to many short-term considerations, they differ fundamentally in the nature of multiple envisaged long-term solution patterns. By compiling relevant underlying contradistinctions, we aim to provide future-oriented incentives for constructive dialectics in practical and theoretical AI safety research.


2008 ◽  
Vol 23 (39) ◽  
pp. 3271-3283 ◽  
Author(s):  
HYE-SUNG LEE

Supersymmetry is one of the best motivated new physics scenarios. To build a realistic supersymmetric standard model, however, a companion symmetry is necessary to address various issues. While R-parity is a popular candidate that can address the proton and dark matter issues simultaneously, it is not the only option for such a property. We review how a TeV scale U(1)′ gauge symmetry can replace the R-parity. Discrete symmetries of the U(1)′ can make the model still viable and attractive with distinguishable phenomenology. For instance, with a residual discrete symmetry of the U(1)′, Z6 = B3 × U2, the proton can be protected by the baryon triality (B3) and a hidden sector dark matter candidate can be protected by the U-parity (U2).


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Marieke Postma ◽  
Graham White

Abstract To obtain a first order phase transition requires large new physics corrections to the Standard Model (SM) Higgs potential. This implies that the scale of new physics is relatively low, raising the question whether an effective field theory (EFT) description can be used to analyse the phase transition in a (nearly) model-independent way. We show analytically and numerically that first order phase transitions in perturbative extensions of the SM cannot be described by the SM-EFT. The exception are Higgs-singlet extension with tree-level matching; but even in this case the SM-EFT can only capture part of the full parameter space, and if truncated at dim-6 operators, the description is at most qualitative. We also comment on the applicability of EFT techniques to dark sector phase transitions.


Significance Although a ceasefire has been in place since October 2020, very little has been done during that time to integrate or demobilise the many armed forces and groups that exist across the country. The obstacles are formidable. Impacts Significant demobilisation and reintegration will not happen in the near term. Local security will continue to rest on fragile political and financial arrangements between armed groups and governing authorities. The current high levels of oil and gas revenue will tend to discourage unrest.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Benjamin P. Dean

PurposeThis inquiry aims to determine the features and mechanisms that specially enable a multiteam system (MTS) to develop ambidexterity that can deal effectively with rapid changes in dynamic environments. The MTS is an emerging organizational unit comprised of tightly integrated networks of teams that may originate from one or more firms. The inquiry also considered how an MTS can engage those features and mechanisms to maximize ambidexterity as dynamic capabilities for increased innovation and long-term adaptation under complex, volatile conditions.Design/methodology/approachThis conceptual inquiry integrates the emerging research on MTSs with theory and studies relating to ambidexterity and dynamic capabilities. This inquiry focuses on the attributes and linkages that specially characterize an MTS. It analyzes these to determine the key mechanisms and interactions enabling and engaging ambidexterity at MTS unit level.FindingsMTSs can engage powerful mechanisms for ambidexterity functioning as dynamic capabilities at meso-organizational level. The attributes and linkages that distinguish an MTS from other units enable it to deal effectively and efficiently with near-term task demands by simultaneously balancing the essential tasks of exploration and exploitation, and by being able to rapidly adapt by reconfiguring taskwork and reallocating resources as required for sustainable innovation and long-term success within a dynamic environment.Practical implicationsThis inquiry provides valuable insights for designing MTSs that are equipped with selected teams, flexible memberships, specialized skills and permeable interfaces. Autonomy for an MTS allows the unit to span internal and external organizational boundaries to gain access to new discoveries and to exchange information and material resources for increased innovation. Ambidexterity as dynamic capabilities facilitates exploitation of current resources by efficiently reconfiguring taskwork and reallocating materials for adaptation and competitive advantage.Originality/valueThis inquiry appears to represent the most integrative effort to examine the underexplored potential of MTSs for developing and engaging ambidexterity functioning as dynamic capabilities. The inquiry appears to be a first effort at articulating a concept of MTS ambidexterity distinct from organizational ambidexterity. The analysis synthesizes a systems model that guides organizational leaders and opens new opportunities for future research.


2021 ◽  
Vol Special issue (1) ◽  
pp. 51-56
Author(s):  
Nigora Djuraeva ◽  

The article presents the results of using a material based on the mineral trioxide unit “Bio-Dent”for the indirect coating of the pulp. It was found that there were no complaints from the use of domestic Portland cement both in the near term (98.8%) and inthe long term after treatment in comparison with materials based on calcium hydroxide (72.5%). Stabilization of the pulp electroexcitability indicators at the level of 10 mkA was noted with the use of the material based on MTA “Bio-Dent”as a medical liner for indirect pulp covering.Keywords: dental pulp,indirect pulp coating, calcium hydroxide, mineral trioxide aggregate, pulp electroexcitability.


2016 ◽  
Vol 13 (1) ◽  
pp. 313-321 ◽  
Author(s):  
A. R. Armitage ◽  
J. W. Fourqurean

Abstract. The carbon sequestration potential in coastal soils is linked to aboveground and belowground plant productivity and biomass, which in turn, is directly and indirectly influenced by nutrient input. We evaluated the influence of long-term and near-term nutrient input on aboveground and belowground carbon accumulation in seagrass beds, using a nutrient enrichment (nitrogen and phosphorus) experiment embedded within a naturally occurring, long-term gradient of phosphorus availability within Florida Bay (USA). We measured organic carbon stocks in soils and above- and belowground seagrass biomass after 17 months of experimental nutrient addition. At the nutrient-limited sites, phosphorus addition increased the carbon stock in aboveground seagrass biomass by more than 300 %; belowground seagrass carbon stock increased by 50–100 %. Soil carbon content slightly decreased ( ∼  10 %) in response to phosphorus addition. There was a strong but non-linear relationship between soil carbon and Thalassia testudinum leaf nitrogen : phosphorus (N : P) or belowground seagrass carbon stock. When seagrass leaf N : P exceeded an approximate threshold of 75 : 1, or when belowground seagrass carbon stock was less than 100 g m−2, there was less than 3 % organic carbon in the sediment. Despite the marked difference in soil carbon between phosphorus-limited and phosphorus-replete areas of Florida Bay, all areas of the bay had relatively high soil carbon stocks near or above the global median of 1.8 % organic carbon. The relatively high carbon content in the soils indicates that seagrass beds have extremely high carbon storage potential, even in nutrient-limited areas with low biomass or productivity.


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