Shedding light on CP violation in the charm system via D to V gamma decays

Recent evidence for direct CP violation in non-leptonic charm decays cannot be easily accommodated within the Standard Model (SM). On the other hand, it fits well in new physics models generating CP violating Delta C=1 chromomagnetic dipole operators. We show that in these frameworks sizable direct CP asymmetries in radiative D to P+ P- gamma decays (P=pi,K), with M_PP close to the rho or the phi peak, can be expected. Enhanced matrix elements of the electromagnetic dipole operators can partly compensate the long distance dominance in these decays, leading to CP asymmetries of the order of several percent. If observed at this level, these would provide a clean signal of physics beyond the SM and of new dynamics associated to dipole operators. We briefly comment on related CP violating observables accessible via time dependent D(Dbar) to P+ P- gamma studies and angular decay product distributions in rare semileptonic D decays.Comment: 5 page

Softened Gravity and the Extension of the Standard Model up to Infinite Energy

Attempts to solve naturalness by having the weak scale as the only breaking of classical scale invariance have to deal with two severe difficulties: gravity and the absence of Landau poles. We show that solutions to the first problem require premature modifications of gravity at scales no larger than $10^{11}$ GeV, while the second problem calls for many new particles at the weak scale. To build models that fulfil these properties, we classify 4-dimensional Quantum Field Theories that satisfy Total Asymptotic Freedom (TAF): the theory holds up to infinite energy, where all coupling constants flow to zero. We develop a technique to identify such theories and determine their low-energy predictions. Since the Standard Model turns out to be asymptotically free only under the unphysical conditions $g_1 = 0$, $M_t = 186$ GeV, $M_\tau = 0$, $M_h = 163$ GeV, we explore some of its weak-scale extensions that satisfy the requirements for TAF.Comment: 60 pages. Final version to appear on JHEP. v3: references adde

The light stop window

We show that a right-handed stop in the 200-400 GeV mass range, together with a nearly degenerate neutralino and, possibly, a gluino below 1.5 TeV, follows from reasonable assumptions, is consistent with present data, and offers interesting discovery prospects at the LHC. Triggering on an extra jet produced in association with stops allows the experimental search for stops even when their mass difference with neutralinos is very small and the decay products are too soft for direct observation. Using a razor analysis, we are able to set stop bounds that are stronger than those published by ATLAS and CMS.Comment: 21 pages, 9 figures. v2: fig. 9b has been updated and revised at large values of the stop/neutralino mass splitting. The discussion of stop co-annihilations has been upgraded including Sommerfeld enhancement

Perceptions of people’s dishonesty towards robots

Dishonest behavior is an issue in human-human interactions and the same might happen in human-robot interactions. To ascertain people’s perceptions of dishonesty, we asked participants to evaluate five different scenarios where someone was being dishonest towards a human or a robot, but we varied the level of autonomy the robot presented. We asked them how guilty they would feel by being dishonest towards a robot, and why do they think people would be dishonest with robots. We see that, regardless of being a human or the autonomy the robot presented, people always evaluated as being wrong to be dishonest. They reported feeling low guilt with a robot. And they expressed that people will be dishonest mostly because of lack of capabilities in the robot to prevent dishonesty, absence of presence, and a human tendency for dishonesty. These results bring implications for the developments of autonomous robots in the future.info:eu-repo/semantics/acceptedVersio

Budging Beliefs, Nudging Behaviour

This is the final version. Available on open access from Springer via the DOI in this record.Nudges have become a popular tool for behaviour change; but, some interventions fail to replicate, even when the identical, previously successful intervention is used. One cause of this problem is that people default to using some of or all of the previously-successful existing nudges for any problem – the “kitchen sink” approach. We argue that the success of an intervention depends on understanding people’s current behaviour and beliefs to ensure that any nudge will actually “budge” them from their current beliefs. We introduce the Beliefs-Barriers-Context (“BBC”) model, with three components: understanding beliefs, barriers, and context to change behaviour through a budge. Designing a budge has the goal of identifying the psychological mechanism that drives a target behaviour, focusing on the psychology of the target population before attempting to change that behaviour. In contrast to the “kitchen sink” approach, budges are best complemented with mechanism experiments to identify what undergirds behaviour change. Moving away from simply nudging behaviour to budging minds—by understanding beliefs, barriers and context—has the potential to inform both the successes and failures of behavioural interventions

Soliton solutions of the Kadomtsev-Petviashvili II equation

We study a general class of line-soliton solutions of the Kadomtsev-Petviashvili II (KPII) equation by investigating the Wronskian form of its tau-function. We show that, in addition to previously known line-soliton solutions, this class also contains a large variety of new multi-soliton solutions, many of which exhibit nontrivial spatial interaction patterns. We also show that, in general, such solutions consist of unequal numbers of incoming and outgoing line solitons. From the asymptotic analysis of the tau-function, we explicitly characterize the incoming and outgoing line-solitons of this class of solutions. We illustrate these results by discussing several examples.Comment: 28 pages, 4 figure

Development of a Novel Piezoelectric Harvester Excited by Raindrops

The impact of raindrops on a dry surface leads to a splashing phenomenon that dissipates a lot of energy. To improve energy collection, a novel piezoelectric raindrop energy harvester equipped with a spoonful of water was developed. The advantages and the drawbacks of this solution were analyzed with the aid of numerical simulations. A series of experimental tests were carried out in a laboratory with simulated raindrops. Experimental results showed that the negative effect of the added water mass was exceeded by the positive effects related to the impact of the raindrop on a liquid surface. Tests carried out connecting the harvester to a resistive load showed that the prototype was able to collect more energy than a simple cantilever harvester