Multiparton scattering at the LHC

The large parton flux at high energy gives rise to events where different pairs of partons interact contemporarily with large momentum exchange. A main effect of multiple parton interactions is to generate events with many jets at relatively large transverse momenta. The large value of the heavy quarks production cross section may however give also rise a sizable rate of events with several $b$-quarks produced. We summarize the main features of multiparton interactions and make some estimate of the inclusive cross section to produce two $b{\bar b}$ pairs within the acceptance of the ALICE detector.Comment: 10 pages, 4 figures, contribution to ALICE PP

b \bar b b\bar b production in proton-nucleus collisions at the LHC

A sizable rate of events, with several pairs of $b$-quarks produced contemporarily by multiple parton interactions, may be expected at very high energies as a consequence of the large parton luminosities. The production rates are further enhanced in hadron-nucleus reactions, which may represent a convenient tool to study the phenomenon. We compare the different contributions to $b{\bar b}b{\bar b}$ production, due to single and double parton scatterings, in collisions of protons with nuclei at the CERN-LHC.Comment: 13 pages, 4 figure

Production and detection of doubly charmed tetraquarks

The feasibility of tetraquark detection is studied. For the cc\bar{u}\bar{d} tetraquark we show that in present (SELEX, Tevatron, RHIC) and future facilities (LHCb, ALICE) the production rate is promising and we propose some detectable decay channels.Comment: 6 pages, 5 figure

Fractional momentum correlations in multiple production of W bosons and of b-anti_b pairs in high energy pp collisions

Multiple parton collisions will represent a rather common feature in pp collisions at the LHC, where regimes with very large momentum transfer may be studied and events rare in lower energy accelerators might occur with a significant rate. A reason of interest in large p_t regimes is that, differently from low p_t, evolution will induce correlations in x in the multiparton structure functions. We have estimated the cross section of multiple production of W bosons with equal sign, where the correlations in x induced by evolution are particularly relevant, and the cross section of b-bar_b b-bar_b production, where the effects of evolution are much smaller. Our result is that, in the case of multiple production of W bosons, the terms with correlations may represent a correction of the order of 40% of the cross sections, for pp collisions at 1 TeV c.m. energy, and a correction of the order of 20% at 14 TeV. In the case of b-bar_b pairs the correction terms are of the order of 10-15% at 1 TeV and of the order of 5% at 14 TeV.Comment: Submitted to Phys. Rev.

Possible explanations for different surface quality in laser cutting with 1 micron and 10 microns beams

In laser　cutting　of　thick　steel　sheets,　quality　difference　is　observed　between　cut　surfaces　obtained　with 1 micron and 10 micron laser beams. This paper investigates physical mechanisms for this interesting and important problem of the wavelength dependence. First, striation generation process is described, based on a 3D structure of melt flow on a kerf front, which was revealed for the first time by our recent experimental observations. Two fundamental processes are suggested to explain the difference in the cut surface quality: destabilization of the melt flow in the central part of the kerf front and downward displacement of discrete melt accumulations along the side parts of the front. Then each of the processes is analyzed using a simplified analytical model. The results show that in both processes, different angular dependence of the absorptivity of the laser beam can result in the quality difference. Finally we propose use of radial polarization to improve the quality with the 1 micron wavelength

Positive impact of mindfulness meditation on mental health of female teachers during the COVID-19 outbreak in Italy

The Covid-19 pandemic and subsequent public health measures were shown to impact negatively on people\u2019s mental health. In particular, women were reported to be at higher risk than men of developing symptoms of stress/anxiety/depression, and resilience was considered a key factor for positive mental health outcomes. In the present study, a sample of Italian female teachers (n = 66, age: 51.5 \ub1 7.9 years) was assessed with self-report instruments one month before and one month after the start of the Covid-19 lockdown: mindfulness skills, empathy, personality profiles, interoceptive awareness, psychological well-being, emotional distress and burnout levels were measured. Meanwhile, they received an 8-week Mindfulness-Oriented Meditation (MOM) course, through two group meetings and six individual video-lessons. Based on baseline personality profiles, analyses of variance were performed in a low-resilience (LR, n = 32) and a high-resilience (HR, n = 26) group. The LR and HR groups differed at baseline in most of the self-report measures. Pre\u2013post MOM significant improvements were found in both groups in anxiety, depression, affective empathy, emotional exhaustion, psychological well-being, interoceptive awareness, character traits and mindfulness levels. Improvements in depression and psychological well-being were higher in the LR vs. HR group. We conclude that mindfulness-based training can effectively mitigate the psychological negative consequences of the Covid-19 outbreak, helping in particular to restore well-being in the most vulnerable individuals

The Chances to Produce and Detect the b-b-ubar-dbar Tetraquark at LHC

In the LHC collider a significant rate of events with double parton scattering is expected. This will be the leading mechanism for production of two b-bbar pairs. We estimate the probability of binding two b quarks into a diquark and the probability of dressing this diquark into a b-b-ubar-dbar ISP=01+ tetraquark. Calculations shows that that this bound state of two B mesons is stable against the strong interaction and has a life time of the order of ps. We estimate that the production rate at luminosity L=0.1 events per second will be about 6 tetraquarks per hour or more.Comment: Contributed talk at the XVIII European Conference on Few-Body Problems in Physics, September 8-14, Bled, Slovenia, 4 pages LaTe

Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space

The scale factor $\sigma_{eff}$, which characterizes double parton collisions in high energy hadron interactions, is a direct manifestation of the distribution of the interacting partons in transverse space, in such a way that different distributions give rise to different values of $\sigma_{eff}$ in different double parton collision processes. We work out the value of the scale factor in a few reactions of interest, in a correlated model of the multi-parton density of the proton recently proposed.Comment: 10 pages, 2 figure

Language control and parallel recovery of language in individuals with aphasia

Background: The causal basis of the different patterns of language recovery following stroke in bilingual speakers is not well understood. Our approach distinguishes the representation of language from the mechanisms involved in its control. Previous studies have suggested that difficulties in language control can explain selective aphasia in one language as well as pathological switching between languages. Here we test the hypothesis that difficulties in managing and resolving competition will also be observed in those who are equally impaired in both their languages even in the absence of pathological switching. Aims: To examine difficulties in language control in bilingual individuals with parallel recovery in aphasia and to compare their performance on different types of conflict task. Methods & procedures: Two right-handed, non-native English-speaking participants who showed parallel recovery of two languages after stroke and a group of non-native English-speaking, bilingual controls described a scene in English and in their first language and completed three explicit conflict tasks. Two of these were verbal conflict tasks: a lexical decision task in English, in which individuals distinguished English words from non-words, and a Stroop task, in English and in their first language. The third conflict task was a non-verbal flanker task. Outcomes & Results: Both participants with aphasia were impaired in the picture description task in English and in their first language but showed different patterns of impairment on the conflict tasks. For the participant with left subcortical damage, conflict was abnormally high during the verbal tasks (lexical decision and Stroop) but not during the non-verbal flanker task. In contrast, for the participant with extensive left parietal damage, conflict was less abnormal during the Stroop task than the flanker or lexical decision task. Conclusions: Our data reveal two distinct control impairments associated with parallel recovery. We stress the need to explore the precise nature of control problems and how control is implemented in order to develop fuller causal accounts of language recovery patterns in bilingual aphasia

The cadaveric studies and the definition of the antero-lateral ligament of the knee: From the anatomical features to the patient-specific reconstruction surgical techniques

Cadaver studies represented a milestone in surgical orthopaedic research, and still today they play a crucial role in the achievement of new knowledge about joint disease behaviour and treatment. In this review, an overview of the cadaver studies available in the literature about the anatomy, role, and treatment of the antero-lateral ligament (ALL) of the knee was performed. The aim of the review was to describe and gain more insight into the part of in vitro study in understanding knee joint anatomy and biomechanics, and in developing surgical reconstruction techniques. The findings of the review showed that cadaver studies had, and will continue to have, a key role in the research of knee joint biomechanics and surgical reconstruction. Moreover, they represent a powerful tool to develop and test new devices which could be useful in clinical and surgical practice