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28 August 2018

A beautiful end for the Higgs boson

An observation made by the CMS experiment at CERN, submitted for publication in Physical Review Letters on August 28th, represents yet another important milestone reached in the scrutiny of the Higgs boson and its interactions with Standard Model particles.

On 4 July 2012, two of the experiments at the CERN’s Large Hadron Collider (LHC), ATLAS and CMS, reported independently the discovery of the Higgs boson. The discovery marked the beginning of an experimental programme aimed at determining the properties of the newly discovered particle. Reporting on Aug 28 at a seminar at CERN, the CMS collaboration announces yet another milestone in that programme, following a recent publication that announced the first observation of the direct Higgs boson coupling to the heaviest Standard Model particle, the top quark.

Although the direct decay of the Higgs boson to bottom quarks (also called beauty quark) is actually the most frequent one of all possible Higgs decays, it has been a real experimental challenge to observe it. This is because there is an overwhelmingly large number of other Standard Model processes (called background) that can mimic the experimental signature characterized by the appearance of a bottom and an anti-bottom quark.

Therefore, in order to allow a significant reduction of the background, it was necessary on one side to focus on particular signal-enriched signatures where a Higgs boson is produced in association with a vector boson (a W or Z particle, as seen in the feature image); and, on the other side, to adopt advanced analysis techniques exploiting deep neural networks and other machine learning tools. Being the process quite rare, it was necessary to sift through a large number of collisions to find the signal. Fortunately, the LHC’s great performance in 2016 and 2017 made this possible.

“It was the ingenuity of CMS scientists in deploying modern sophisticated analysis tools, including machine learning techniques, and in combining the aforementioned signature with other sensitive Higgs boson processes, as well as the outstanding performance of the detector and the very large available data set, that made it possible to pass this milestone earlier than expected”, says CMS elected Spokesperson Roberto Carlin, full professor at Padova University and researcher of INFN Padova.

Once more, this measurement confirms the predictions of the Standard Model. The present uncertainty on the decay rate is however still large, leaving wide possibilities for the improvements expected in the next decade during the so called “Phase 2” of LHC operations.

In the feature image the illustration of a candidate event showing the associated production of a Higgs boson and a Z boson, with the subsequent decay of the Higgs boson to a bottom quark and its antiparticle.

13 July 2018

Detected for the first time neutrinos and photons from the same cosmic source

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For the first time ever a possible source for cosmic neutrinos has been identified thanks to its association to a source of gamma rays with very high energies. The source is a so-called blazar, an active galaxy with an extremely massive black hole of several hundreds of milions of solar masses at its centre. It is located at a distance of 4.5 billion light years from the Earth in direction of the Orion constellation. The extraordinary discovery, published in Science, has become possible thanks to the combination of data with different origin: from the neutrino detector IceCube, taking data at the South Pole, and from another 15 experiments detecting photons on the Earth and in Space.

Important contributions to the discovery have been made by the researchers of the National Institute of Astrophysics (INAF), the National Institute for Nuclear Physics (INFN), the Italian Space Agency (ASI) and various Italian universities that are involved in these experiments.

The result has been made possible by the “choral” work at the frontier of astronomy, the multimessenger astronomy, which not only observes electromagnetic radiation at all wavelenghts (radio, microwave, infrared, visible, UV, X-rays and gamma) but also gravitational waves, cosmic rays and neutrinos. The discovery is a solid indicator towards the solution for one of the greatest enigmas of astrophysics: the origin of cosmic rays with extremely high energies.

The turning point towards this extraordinary discovery dates back to September 2017, when the IceCube detector observed for the first time an interesting neutrino which was then given the name IC-170922A. Its very high energy of 290 TeV (terraelectronvolt, one thousand billions of electronvolt) indicated that most probably its origin had to be a very “active” distant object. It was expected that the production of cosmic neutrinos was accompanied by gamma rays. For this reason, right after the identification of the neutrino, IceCube launched a “neutrino alert” to all telescopes operating on Earth and in Space. The hope was that their observations could help identify with precision the source. And indeed this was the case.

The Fermi satellite, realized by NASA with an important participation of the National Institute of Astrophysics (INAF), the National Institute of Nuclear Physics (INFN) and the Italian Space Agency (ASI), succeeded in localising the emission of gamma radiation coinciding with a known source with the precision of one tenth of a degree by observing with its Large Area Telescope (LAT) the extremely high energy gamma rays in the direction of the neutrino source. The source was a blazar with an Active Galactic Nucleus (AGN), that is an extremely massive black hole at the center of a galaxy, that expels a jet of radiation and matter in our direction at almost the velocity of light. Also Fermi-LAT launched an alert right away. This allowed for several experiments to point to the source. Amongst these were the MAGIC telescopes. Turning their gigantic mirrors towards the identified source they can measure the emission spectrum at an energy which is a thousand times higher than the spectrum observed by Fermi-LAT, adding this way another important piece to this discovery.

Thanks to all these different observations, it was possible to identify the blazar TXS 0506+056 as the source of neutrino IC-170922A. The distance of the galaxy from the Earth was measured by a group of researchers lead by the Padova divison of INAF.

The observation not only of the gamma rays but also of a high energy neutrino allows to assert that the AGN jets contain also extremely high energy protons. The IC-170922A neutrino helps to partially solve the great mystery about the very high energy cosmic rays and confirms the idea of a strong relation between the various cosmic messengers.

The study of cosmic rays has a long tradition in Padova, dating back to the 30s when Bruno Rossi started to investigate this field of research. Also the local division of the INFN has been actively involved from its first days on. The understanding of the origin of cosmic rays and that of the messengers of those regions in the Universe where, under extreme conditions, particles of extraordinary energies are produced and accelerated, has motivated the Padova INFN division to get involved since the beginning in the Fermi-LAT and MAGIC projects, with the latter studying the gamma rays originating from celestial sources from Earth through the detection of Cherenkov radiation.

This particular scientific discovery has been made possible also thanks to the work of researchers from Padova, both on the identification of the neutrino source as well as on the study of the spectrum of the emitted electromagnetic radiation at highest energies with the MAGIC telescopes.

Also worth mentioning is the remarkably faresighted work of Milla Baldo Ceolin in Padova. She gave significant contributions to this field of research, starting also an important series of workshops on these topics aimed at discussing its prospectives. The first “International Workshop on Neutrino Telescopes: another way to observe the universe” was held in 1988 at the Istituto Veneto di Scienze, Lettere ed Arti in Venice. Today the conference series has arrived at its 18th edition, carried on by her students and research collaborators.

In the feature image the reproduction of a blazar. Credits: NASA/JPL-Caltech, https://photojournal.jpl.nasa.gov/catalog/PIA16695

Artistic reproduction of the observed event.

Artistic visualisation of the observation.

The MAGIC telescopes. (Credits: IAC, http://www.iac.es/copyright.php?lang=en)

I ricercatori italiani della collaborazione MAGIC

The Italian researchers of the MAGIC collaboration.

The FERMI experiment (Credits: NASA https://www.nasa.gov/multimedia/guidelines/index.html)

One of the MAGIC telescopes.

29 June 2018

The “Muon Collider Workshop” at Padova

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Prof. Carlo Rubbia, the 1984 Nobel prize winner in physics, will give the keynote talk at the “Muon Collider Workshop” taking place at the Auditorium of the Orto Botanico in Padova on July 2-3.

The event, envisaged within the ARIES European Project framework, is organized by the researchers operating at the Padova Division of the National Institute for Nuclear Physics (INFN) and the Department of Physics and Astronomy of the University, involved in the project.

The two-days workshop will focus on the promising options to build a large muon collider at very high energy for the forefront research in fundamental physics. Muons are very familiar particles, being part of the cosmic radiation flow that constantly surrounds us.

There is a great interest in producing muons abundantly and letting them collide, like the protons at the CERN LHC do, as these particles could be exceptionally useful means to explore and understand more deeply the Higgs boson properties. Furthermore, they would act as a very intensive neutrino beam “factory”.

Conceptually appealing, these innovative ideas require researchers to cope with very strong and challenging efforts to develop new technologies and instruments.

Prof. Rubbia, who has studied the issue from an original perspective, will illustrate the important role that the muon collider could have for Particle Physics in the next future.

Further information:
https://indico.cern.ch/event/719240/
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Phone +39 0498277129

19 June 2018

INFN proposal ranked among the best technology transfer projects selected by the Regione Veneto

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The technology transfer project proposed by INFN and the Department of Industrial Engineering of the University of Padua ended up among the top ranked by the Regione Veneto in the evaluation of proposals submitted to the annual call POR-FSE 2014/20.

With the funds obtained, two young engineers will be hired for one year in a post-doc position dedicated to technological research and, after an initial period of training-on-the-job by the INFN Mechanical Design Group and the Metallographic Analysis Laboratory of the Engeneering Dept., they will dedicate their efforts to the development of innovative additive manufacturing applications in two sectors that are seminal for the local industrial fabric: biomedical appliances and fashion related products.

INFN, a Research Institution that has been granted by the Regione Veneto the status of “Centro di Formazione Superiore” (Higher Education Center), constantly participates in European, National and Regional projects that focus on innovation and technology transfer, thus contributing with a proactive attitude to the dissemination of technical knowledge and technologies to Industrial partners. Recently, in the context of the Industry 4.0 Initiative, INFN has promoted R&D activities in strategic innovative sectors like micro–mechanics, thermal and surface treatments and additive manufacturing technologies, where significant competences have been built up via the engagement in cutting edge scientific projects.

This project fits in the course started in 2016 to explore the potential of additive manufacturing for metallic materials, a revolutionary approach that opens the way to fast prototyping and to the development of new geometrical patterns so far not even conceivable, simplifying the design and shortening the step leading to final production.

The route taken by INFN in collaboration with Padua University Departments, has led to the creation of the DIAM Lab that is devoted to the development of these technologies and to material research while offering to the academic research community as well as to local businesses its competences and the access to the SLM 3D printers for R&D goals.

In the feature image the picture of a prototype of a very high efficiency beam-dump component, manufactured in ultra-pure copper for the SPES facility at the LNL INFN Laboratories by DIAM researchers as part of the POR-FSE 5687-1-2121-2015 project (in collaboration with Officina dei Materiali SaS and SISMA SpA).

6 June 2018

Heavy Weigths World Match

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The challenge was raised for a long while: who would first observe the interaction of the Higgs boson with the top quark, the two heaviest elementary particles known so far? (The Higgs mass exceeds that of a bunch of 130 protons, the top even 180).

Indirect evidence has been around for a while, but only on April 8th the CMS collaboration could claim the unambiguous observation of a sufficient number of events where the Higgs was produced coupled to a top-antitop pair out of billions of proton proton collisions at the Large Hadron Collider at CERN.

The result was soon after sent for publication to Physical Review Letters, and published on June 4th. The article was highlighted as PRL Editor\’s Suggestion and was accompanied by a comment article.

This result, confirmed just these days by an independent measurement by another LHC experiment, ATLAS, was highlighted on Monday 4th by professor Roberto Carlin, the elected spokeperson of the CMS collaboration, full professor of General Physics in the University of Padova, during the VI International Conference on LHC Physics, an assembly of more than 400 LHC Physicists who meet these days in Bologna to discuss LHC results. The CMS members from Padova University and our division constitute one of the largest groups of the CMS collaboration.

The Higgs boson was discovered in July 2012 simultaneously by ATLAS and CMS. It is the keystone of the electroweak theory of fundamental interactions. Each particle in the theory gains its mass through the interaction with the Higgs, so that a simple relation can be stated between the particle mass and its coupling to the boson. Checking this relation, by measuring independently masses and couplings, provides a strong test of the theory.

While the top and the Higgs masses are precisely known, the measurement of their coupling is very difficult, because the process is very rare (it happens once in hundred Higgs events, and Higgs production happens once in a billion proton proton collisions at the LHC); in addition, top and Higgs are observed in very complicated topologies. A lot of different decay modes have been independently inspected by several research groups, and only at the end the individual results have been merged to allow the discovery. The measurement confirms the theory prediction with about 25% accuracy.

\”The result we achieved was expected only in the far future, for the so called second phase of LHC operations. We face a transition from discovery to precision measurement, the challenge is to reach few percent precision in most of Higgs couplings to the other particles. In the next decades we expect to collect about forty times the events analyzed so far, with a much improved detector. We aim to observe the coupling of the Higgs boson with particles as light as the muons, and the Higgs self-coupling . Besides clarifying beyond any doubt the way mass is provided to elementary particles, this will throw light upon possible extensions of the electroweak theory and will drive the future steps in accelerator Physics\”, says Prof. Carlin.

An event candidate for the production of a top quark and top anti-quark pari in conjunction with a Higgs Boson in the CMS detector. The Higgs decays into a tau+ lepton and a tau- lepton; the tau+ in turn decays into hadrons and the tau- decays in an electron. The decay product symbols are in blue. The top quark decays into three jets (sprays of lighter particles) whose names are given in purple. One of these is initiated by a b-quark. The top anti-quark decays into a muon and b-jet, whose names appear in red.

31 May 2018

Quark-Gluon Plasma on the red carpet for the Quark Matter 2018 conference in Venice

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The Quark Matter 2018 international conference closed a few days ago in Venice. About 850 researcher from all over the world took part in the conference, which was organised by Istituto Nazionale di Fisica Nucleare (INFN), with our Padova division on the forefront, together with several Italian universities.

Palazzo del Cinema was the stage of this 27th edition of Quark Matter, where the latest studies on the Quark-Gluon Plasma were reported. This is the state of matter that constituted our Universe a few microseconds after the big bang, before the particles that compose atomic nuclei formed.

In order to study this primordial state of matter, physicists use particle accelerators, as the CERN Large Hadron Collider (LHC), at which hundreds of Italian researchers work, coordinated by INFN. These large accelerators can collide heavy nuclei at very high energies, to reproduce conditions similar to those of the primordial Universe.

During the conference experiments at the LHC reported new measurements obtained from the analysis of data collected in the past two years. These included the first results from collisions of xenon nuclei (with mass number A=129) at the LHC and their comparison with similar measurements obtained with the larger lead nuclei (A=208).

The ALICE Colllaboration reported several results to which physicists of the Padova unit contributed and which are described in about twenty new articles. Among the most interesting and debated results there are measurements of the production of light nuclei and antinuclei and of hadrons that contain a charm quark. These measurements provide crucial insight on the interactions of different quark species with the Quark-Gluon Plasma and on the production of composite particles (hadrons and light nuclei) from the cooling and expanding Plasma.

il team organizzatore di QuarkMatter 2018

29 May 2018

Quark Matter 2018: team work at its best

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The conference Quark Matter 2018, at Lido di Venezia from May 13 to 19, is over.

The feedback we are receiving in these days is absolutely positive. And it is great to receive compliments from friends and colleagues from all over the world. When the result is appreciated like this it makes you realise that more than two years of work, commitment and dedication have brought their fruits.

And you also understand that the result is not something attributable to single people that have contributed with their specific task to the realisation of this or that aspect of the event. Instead, what really counts is the perfect synergy of all those involved, the magic fit of all the single pieces of this multi-coloured puzzle that the organisation of such a complex and ample event constitutes.

The team work that is behind the realisation of Quark Matter 2018, exhausting and, not so granted in other work contexts, confirms an idea that is predominant inside INFN in general and at the Padova division in particular: united you always win.

Collaboration, understanding, exchange, together with passion for our work and a competence growing with time have justified all the efforts and strains of the last months. And it leaves you with a great sense of appreciation for the individual contributions and the strength that derives from the beauty of being part of a well tuned team.

Giuseppina Salente and Rossana Chiaratti – QM18 Secretariat

il team d'accoglienza di QuarkMatter 2018

28 May 2018

Proposal for competence center approved

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The proposal for SMACT, the competence center of the Universities and research institutions in the Triveneto area, has been approved for negotiation by the Ministry of Economical Development (MISE).

The Ministry has published the ranking of the proposals that have been approved for negotiation for the creation of highly specialised competence centres on Industry 4.0 themes. Among the proposals that have passed the selection there is also the one that had been submitted by the University of Triveneto together with the INFN with its Padova division and the Legnaro Laboratories, and the Bruno Kessler foundation.

The highly specialised competence centres on Industria 4.0 themes will carry out orientation and training activities for companies as well as provide support for the implementation of projects in the fields of innovation, industrial research and experimental development, aimed at the realisation (or improvement) of new products, processes or services using advanced technology within the framework of Industria 4.0.

The SMACT centre in particular is centred on the field of informatics and the competence contribution by INFN will be focused on Cloud computing, Advanced Analytics and Big Data.

The project foresees an investment of about 7.5 million Euros by the ministry, covering all costs related to personnel, laboratories and equipment for three years. It is strongly supported by the substantial investment of the 30 companies that have joined the proposal as technology providers and industrial partners.

The project sees the collaboration of the University of Padova as head of the partnership, University of Verona, Ca\’ Foscari University of Venice, University of Trento, SISSA (Scuola Superiore Internazionale di Studi Avanzati) Trieste, Free University of Bolzano, University of Udine, University IUAV of Venice, Bruno Kessler Foundation Trento, National Institute of Nuclear Physics – Padova Division and Laboratories of Legnaro.

There are 30 private partners that will collaborate on the project: ACCA software, Adige, Aspiag Service, Brovedani, CAREL Industries, Corvallis, Danieli & C. Officine Meccaniche, DBA lab, Electrolux Italia, EnginSoft, Eurosystem, Gruppo PAM, Innovation Factory, Intesa Sanpaolo, Keyline, Lean Experience Factory, Microtec, Miriade, Omitech, Optoelettronica Italia, OVS, PricewaterhouseCoopers Advisory, SAVE, Schneider Electric, TEXA, TFM Automotive & Industry, Thetis, TIM, Umana, Wartsila Italia.

28 May 2018

Quark Matter 2018 at Venice

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The 27th edition of the Conference, organized by INFN Sezione di Padova, will take place in Venezia Lido, at the Palazzo del Cinema and Palazzo del Casinò (Venice Convention Center), on 13-19 May 2018.
The two buildings are worldwide famous for being the venue where the “Venice International Film Festival” is held every year.

Quark Matter 2018 -the XXVIIth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions- brings together physicists from around the world to discuss new developments in high energy heavy-ion physics. The focus is on the fundamental understanding of strongly-interacting matter at extreme conditions of high temperature and density, as formed in ultra-relativistic nucleus-nucleus collisions. In these conditions, which also characterised the early Universe, matter appears as a Quark-Gluon Plasma, with quarks and gluons not confined within hadrons.

Visit the Conference website for more information about the event and the Scientific Program.

28 May 2018

Three days of beer and science

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Three nights, three scientific subjects, three pubs: this is Pint of Science, this year for the second time in Padova, simultaneously with other 22 Italian cities and 21 nations all over the world. From May 14 to 16, 9 scientific talks about physics, astronomy, biology, technology and much more were presented to the public.

The Old England in via Manzoni hosted the section “Atoms to Galaxies”, where we talked about physics and astronomy, from the microscopic world of particles to the signals that arrive from the Universe. At the Vizio in via San Biagio we discovered the mysteries of human biology with the subject “Our Body”, while at the Canevone in via Umberto I we explored the frontiers of technology, from nanoparticles to exoskeletons, with “Tech me Out”.

«The researchers can\’t wait to share their work with the rest of the world and they have fun doing it. Pint of Science is not only an occasion, but also a challenge: it means explaining difficult subjects in a simple way, in a contest that is completely different from the one the researchers are used to» explains Michele Michelotto, local coordinator of Pint of Science and tecnologist at our division.

Also two of our researchers accepted the challenge and participated with a talk. Emanuele Michielin told us about \”Beauty and Charm to explore the origin of the Universe\” and Giacomo Ciani presented \”The cosmic forge of gold: history of stars, cataclysms and gravitational waves\”. The INFN is also one of the sponsors at national level.

Emanuele Michielin at the Old England.

Giacomo Ciani talks about the discovery of gravitational waves.