DOE-INFN Summer Exchange Program for 2018

Founded in 1955, the Frascati National Laboratories (LNF) are the oldest and largest laboratories of INFN, the Italian agency devoted to fundamental research in nuclear and subnuclear physics. The LNF cover an area of 140000 m² and are located about 20 km from the centre of Rome. They can be easily reached by car, by plane (two international airports), by bus and by train. Research activities in the LNF are pursued in all major INFN areas of interest: Particle Physics, Astroparticle Physics, Nuclear Physics, Theoretical Physics and Detector Physics. Several groups are participating in experimental programs in collaboration with US institutions.
Candidates must be enrolled as students at a US University and must have begun, at the time of application, at least the third year of a US University curriculum in physics, engineering or computing science. They can join a team at the LNF for 2 months between June 1^st and October 31^st, 2018. For further details refer to the Summer Exchange Program homepage. Opportunities include participation in physics analysis, activities of running experiments as well as involvement in detector developments.

The Frascati Laboratories will be closed from August 6th to August 17th.

The 15 available positions at Frascati are the following:

1 position: CYGNUS-RD

Title: Dark Matter Search

Description: CYGNUS-RD is the name of the innovative detector R&D aimed to merge the technique of negative ion field gage with optical triple-gem readout, proposed for dark matter direction search in the CYGNUS international collaboration. A peculiar modification of conventional TPC involves the addition to the gas mixture of a highly electronegative molecule, making it a Negative Ion TPC. When negative ions act as image carrier instead of electrons, diffusion is reduced to the thermal limit without the need for a magnetic field implying a better track reconstruction. The optical readout with CMOS sensor can provide very high granularity (higher then chip pixels) and with the proper camera aperture and focal lent can image large area at lower cost. The purpose of the stage is collaborate on the analysis of the first prototypes results, developing appropriate algorithms end exploring the possibility to implements machine learning methods.

Tutor: Giovanni Mazzitelli (Giovanni.Mazzitelli@lnf.infn.it)

Recommended period: June - July

2 positions: MoonLIGHT-2 & SCF_Lab

Title: Space Research with the MoonLIGHT-2 experiment and the SCF_Lab test facility

Description: The space research activities of the SCF_Lab test facilities are describe at http://www.lnf.infn.it/esperimenti/etrusco/. The goal of MoonLIGHT-2 (Moon Laser Instrumentation for General relativity High-accuracy Tests for the International Lunar Network – Phase 2) is the development, space characterization and deployment of 2nd generation laser retroreflectors for the sub-mm-precision orbit determination of the Moon through a laser-pulse time-of-flight measurement, in order to achieve a high-accuracy test of General Relativity and new theories of gravity. This discipline, called Lunar Laser Ranging (LLR), started 40 years ago, when the Apollo and Lunokhod missions deployed retroreflectors on the surface of the Moon. LLR data are freely available and provide the best overall test of General Relativity with a single experiment (weak and strong equivalence principle, PPN parameter beta, geodetic precession, deviations from the inverse-square law, time variation of the gravitational constant G, extensions of General Relativity). The experiment is an international collaboration between Italian and US institutions. The latter include: the University of Maryland at College Park (UMD), which was Principal Investigator of the 1st generation retroreflectors; the Harvard-Smithsonian Center for Astrophysics, MA, USA (CfA), which has developed the powerful Planetary Ephemeris Program capable (among many other things) of accurately tracking the Moon orbit; the University of California at San Diego, CA, USA (UCSD), which leads the best LLR station, located in USA, called APOLLO (Apache Point Observatory LLr Operation; http://www.physics.ucsd.edu/~tmurphy/apollo/). We have space agency and commercial lunar landing mission opportunities starting from late 2018. See also http://www.lnf.infn.it/divric/Moonlight2.pdf .

For Mars science (gravity, geodesy) and exploration we built and space-qualified INRRI-EDM/2016 (INstrument for landing/Roving laser Retroreflector Investigations) the first-ever laser retroreflector to be deployed on the surface of the red planet by the ESA/ASI ExoMars EDM 2016 mission. INRRI is a compact, lightweight, passive and maintenance-free array of laser retroreflectors of very long lifetime, installed on the external, zenith-facing surface of the ExoMars EDM, with unobstructed view to orbit. INRRI will enable the EDM to be laser-located from Mars orbiters operational either during the EDM lifetime and/or after the EDM end-of-life. INRRI is provided by ASI and INFN-LNF. Another such payload delivered in 2017 by INFN to NASA-JPL through ASI, will be launched on NASA's InSight Mars Lander in 2018; a third one will be delivered to NASA-JPL for launch on NASA's Mars 2020 Rover in 2020.

The student will participate in the: (1) thermal-optical-vacuum test, space qualification and data analysis of new laser retroreflectors for general relativity and space geodesy, to be launched with lunar, near-Earth and martian mission; and/or (2) analysis of LLR data acquired from existing Apollo/Lunokhod payloads for precision gravity tests, as well as with our next-generation lunar laser retroreflectors.

References:
1.Creation of the new industry-standard space test of laser retroreflectors for GNSS and LAGEOS, S. Dell'Agnello, et al., J. Adv. Space Res. 47 (2011) 822–842.
2.A Lunar Laser Ranging Retroreflector Array for the 21st Century, D. Currie, S. Dell'Agnello, G. Delle Monache, Acta Astron. 68, 667– 680 (2011).
3.Advanced Laser Retroreflectors for Astrophysics and Space Science, Dell'Agnello, S., et al (2015), Journal of Applied Mathematics and Physics, 3, 218-227.
4.LaRRI: Laser Retro-Reflector for InSight Mars Lander, S. Dell'Agnello et al., Space Research Today N. 200, 25-32, December 2017.

Tutors: Simone Dell'Agnello (simone.dellagnello@lnf.infn.it) and/or Giovanni Delle Monache (dellemon@lnf.infn.it)

Recommended period: June-July or September-October

1 position: Exotic atoms studies with SIDDHARTA-2

Title: Exotic atoms studies at the DAFNE collider with the SIDDHARTA-2 experiment

Description: SIDDHARTA-2 experiment aims to perform the first measurement in the world of the X-ray transitions in the kaonic deuterium exotic atom, which will help to understand the strong interaction described by the Quantum ChromoDynamics (QCD) theory in the non-perturbative regime in systems with “strangeness” (i.e. with strange quarks). The SIDDHARTA-2 experiment will measure the X rays produced in the de-excitations of kaonic deuterium by using new Silicon Drift Detectors developed to perform precision X-ray spectroscopy and which can have applications going from physics and astrophysics to industry and medicine. SIDDHARTA-2 will be in installed on DAFNE, an electron-positron collider delivering kaons, starting with summer 2018; a very exciting period will then follow! The kaonic deuterium measurement plays a fundamental role in understanding how QCD works, with implications going from particle and nuclear physics to astrophysics (equation of state of neutron stars).

The student will be involved in all the exciting phases of the experiment, from the installation on the DAFNE collider, one of the very few working colliders in the world, to tests of the detector systems and data acquisition. He/she will be also introduced to data analyses and advanced Monte Carlo simulations.

Tutor: Catalina Curceanu (catalina.curceanu@lnf.infn.it)

Recommended period: September - October

1 position

Title: Search for dark matter signals at LNF with PADME

Description: There are models attempting to solve the dark matter problem, as well as the muon (g-2) anomaly, that have postulated the existence of a low-mass spin-1 particle (A’) that would possess a gauge coupling of electroweak strength to dark matter, and a much smaller coupling to the Standard Model (SM) hypercharge. The PADME experiment, by using the positrons of the LNF LINAC, aims at searching for invisible decays of the dark photon by measuring the final state missing mass in the process e^+e^- -> gamma A', with A’ undetected. The measurement requires the determination of the 4-momentum of the recoil gamma, performed using a homogeneous, highly segmented BGO crystals calorimeter, and the rejection of all possible source of background. PADME is an international collaboration that comprises Bulgarian, Hungarian, Italian and American researchers. The detector, presently under construction at the Frascati National Laboratory, will start its first data taking in the late spring of 2018. This is only the first phase of the experiment. Plans, foreseeing the installation on a higher energy beam line at the Cornell University, are also under discussion.

Activity: The student will take part to the data taking and data analysis activities at the Frascati National Laboratory.

Tutor: Paola Gianotti (paola.gianotti@lnf.infn.it)

Recommended period: June - July

1 position

Title: Nanosensors for biomedical applications

Description: Electrochemical DNA – sensors are one of the most promising tools with very diverse areas of application such as medical diagnostics, environmental pollutants monitoring, biological weapons defence etc. In spite of DNA – sensors already widely used in practice, they have a perspective for the improvement of functionality and cost – effectivity. One of the important directions in this matter is the increasing selectivity and sensitivity of sensors in expense of enhancement of electric signal and target – probe hybridization stability. Another important direction is the improvement of the electrode effectivity and manufacturability. From this point of view the best choice is the polymer – CNT enhanced nanocomposites, combining these two important features. At the same time, the better understanding of molecular mechanisms behind the DNA and RNA hybridization on the surface of electric transducer, and polymer – CNT nanocomposites formation is relevant for the improvement of effectivity and manufacturability of DNA – sensors. The Student will carry out all-round activity in nanoscience, with a specific calling for technological applications, stemming from scientific achievements and with the help of a careful theoretical research and modeling activity.

The Student will also participate to the realization of the Nanomaterial (e.g. carbon nanotubes and graphene) that are synthesized in the nanotechnology laboratory, and the corresponding biosensor nano-devices, which he will subsequently characterize and test. The student will engage in the Chemical Vapour Deposition of carbon nanotubes (CNT) and Graphene on catalytic substrates and/or in porous templates, as well as in the arc discharge synthesis of carbon nanotubes, without impurities and with a low density of defects. Purification and functionalization of carbon nanotubes are carried out by LNF team by physical and chemical methods.

Main references:
1. "Biological interactions of carbon-based nanomaterials: From coronation to degradation" Kunal Bhattacharya, Sourav P Mukherjee, Audrey Gallud, Seth C Burkert, Silvia Bistarelli, Stefano Bellucci, Massimo Bottini, Alexander Star, Bengt Fadeel, Nanomedicine: Nanotechnology, Biology and Medicine, Available online 17 December 2015.
2. "Multiwalled carbon nanotube buckypaper induces cell cycle arrest and apoptosis in human leukemia cell lines through modulation of AKT and MAPK signaling pathways", Simona Dinicola, Maria Grazia Masiello, Sara Proietti, Pierpaolo Coluccia, Gianmarco Fabrizi, Alessandro Palombo, Federico Micciulla, Silvia Bistarelli, Giulia Ricci, Angela Catizone, Giorgio De Toma, Mariano Bizzarri, Stefano Bellucci, Alessandra Cucina, Toxicology in Vitro 7 (2015) 1298-1308
3. "Collapse and hybridization of RNA: View from replica technique approach", Y Sh Mamasakhlisov, S Bellucci, Shura Hayryan, H Caturyan, Z Grigoryan, Chin-Kun Hu, The European Physical Journal E 38 (2015) 1-9.
4. "Growth inhibition, cell-cycle alteration and apoptosis in stimulated human peripheral blood lymphocytes by multiwalled carbon nanotube buckypaper", O Zeni, A Sannino, S Romeo, F Micciulla, S Bellucci, MR Scarfi, Nanomedicine 10 (2015), 351-360
5. "Differences in cytotoxic, genotoxic, and inflammatory response of bronchial and alveolar human lung epithelial cells to pristine and COOH-functionalized multiwalled carbon nanotubes", Cinzia Lucia Ursini, Delia Cavallo, Anna Maria Fresegna, Aureliano Ciervo, Raffaele Maiello, Giuliana Buresti, Stefano Casciardi, Stefano Bellucci, Sergio Iavicoli, BioMed Research International,Volume 2014 (2014), Article ID 359506, 14 pages
6. "Targeted Nanodrugs for Cancer Therapy: Prospects and Challenges", Massimo Bottini, Cristiano Sacchetti, Antonio Pietroiusti, Stefano Bellucci, Andrea Magrini, Nicola Rosato, Nunzio Bottini, J. Nanosci. Nanotechnol 14 (2014) 98-114

Tutor: Stefano Bellucci (bellucci@lnf.infn.it)

Recommended period: June - July or September - October

1 position

Title: Electron beam acceleration for advanced materials characterization

Description: With the advent of the era of graphene, the universally famous two-dimensional allotrope of carbon, with its lightweight, amazing strength and unsurpassed ability to conduct electricity and heat better than any other material, previously unconceivable technological opportunities are opening up in a manifold of various applicative areas, in the true spirit of enabling technologies. The use of graphene can be envisaged in nanoelectronics, as a promising alternative to customary materials such as copper, which show well-known limitations in their utilization at the nanometer scale, owing to the challenges of dealing with higher values of frequencies and smaller sizes in beyond state of the art applications. Features like tunable electronic properties may be exploited to realize, for instance, a microwave electronically tunable microstrip attenuator. Electronic systems intended for Aerospace and Aeronautics applications are requested to exhibit such high performances in terms of operating conditions and reliability, that the used materials must retain outstanding mechanical, thermal and electrical properties. New technological solutions must provide significant reduction of weight of parts and supports (such as electronic cases), realized with optimized shapes. A solution to such problems can be provided by exploiting the recent advances in Nanotechnology in the synthesis of the so-called nanocomposites, a class of composites where one or more separate phases have one dimension in the nanoscale (less than 100nm).

The Student will also participate to the Fourier Transform Infrared spectroscopy, and the Electron and atomic force microscopy, characterizations of the nanomaterials, e.g. graphene, nanotubes, and epoxy nanocomposites. The Student will become experienced with modelling and simulation of the CNT growth over catalyst patterned substrates and porous templates, along with the conductance properties of CNT/metal junctions, as well as in modelling CNT electron transport properties. The Student will engage in the realization and characterization of epoxy resin nanocomposites based on nanocarbon materials. and study their electrical and mechanical properties and the electromagnetic shielding they provide in the microwave frequency range.

Main references:
1. "What does see the impulse acoustic microscopy inside nanocomposites?" VM Levin, YS Petronyuk, ES Morokov, A Celzard, S Bellucci, PP Kuzhir, Physics Procedia 70 (2015) 703-706
2. "Microstructure, elastic and electromagnetic properties of epoxy-graphite composites", SS Bellucci, F Micciulla, VM Levin, Yu S Petronyuk, LA Chernozatonskii, PP Kuzhir, AG Paddubskaya, J Macutkevic, MA Pletnev, V Fierro, A Celzard, AIP Advances 5 (2015) 067137
3. "Broadband Dielectric Spectroscopy of Composites Filled With Various Carbon Materials", Stefano Bellucci, Silvia Bistarelli, Antonino Cataldo, Federico Micciulla, Ieva Kranauskaite, Jan Macutkevic, Juras Banys, Nadezhda Volynets, Alesya Paddubskaya, Dmitry Bychanok, Polina Kuzhir, Sergey Maksimenko, Vanessa Fierro, Alain Celzard, IEEE Transactions on Microwave Theory and Techniques, 63 (2015) 2024-2031
4. "Nanocomposites of epoxy resin with graphene nanoplates and exfoliated graphite: Synthesis and electrical properties", A Dabrowska, S Bellucci, A Cataldo, F Micciulla, A Huczko, physica status solidi (b) 251 (2014), 2599-2602.
5. "Heat-resistant unfired phosphate ceramics with carbon nanotubes for electromagnetic application", Artyom Plyushch, Dzmitry Bychanok, Polina Kuzhir, Sergey Maksimenko, Konstantin Lapko, Alexey Sokol, Jan Macutkevic, Juras Banys, Federico Micciulla, Antonino Cataldo, Stefano Bellucci, physica status solidi (a) 211 (2014), 2580-2585
6. "Multi-walled carbon nanotubes/unsaturated polyester composites: Mechanical and thermal properties study", MSI Makki, MY Abdelaal, S Bellucci, M Abdel Salam, Fullerenes, Nanotubes and Carbon Nanostructures 22 (2014), 820-833

Tutor: Stefano Bellucci (bellucci@lnf.infn.it)

Recommended period: June - July or September - October

1 position

Title: NanoElectromagnetics (microwave/RF/photonics)

Description: We have experience in the frequency (energy)/time-domain full-wave multiphysics modeling of the combined electromagnetic-coherent transport problem in carbon-based (graphene, CNT) nano-structured materials and devices. The core concept is that while the advancement of research in this area heavily depends on the progress of manufacturing technology, still, the global modeling of multi-physics phenomena at the nanoscale is crucial to its development. Modeling, in turn, provides the appropriate basis for design. The bridge between nanosciences and the realized circuits can be achieved by using the panoply of microwave/RF engineering at our disposal. From the theoretical models and techniques, we produced efficient software for the analysis and design.

In our models, the quantum transport is described by the Schrödinger equation or its Dirac-like counterpart, for small energies. The electromagnetic field provides sources terms for the quantum transport equations that, in turn, provide charges and currents for the electromagnetic field. In the frequency-domain, a rigorous Poisson-coherent transport equation system is provided, including electrostatic sources (bias potentials). Interesting results involve new concept-devices, such as Graphene-Nano-Ribbon (GNR) nano-transistors and multipath/multilayer GNR circuits, where charges are ballistically scattered among different ports under external electrostatic control. Further examples are given by the simulation of cold-cathodes for field emission based on graphene and by the analysis of optical emission/absorption by single or few layers GNR.

Recently, we began to work on the model of the graphene/CNT-metal transition and related equivalent circuits models, ii) the inclusion of thermal effects in graphene/CNT, e.g. as deriving from ballistic path reduction due to phonon scattering and as arising at the contact between graphene and silicon dioxide. In the time-domain, we now avail a novel Schrödinger/Dirac-based transmission line matrix (TLM) solver for the self-consistent analysis of the electromagnetic-coherent transport dynamics in realistic environments. It is highlighted that the self-generated electromagnetic field may affect the dynamics (group velocity, kinetic energy etc.) of the quantum transport. This is particularly important in the analysis of time transients and in the describing the behavior of high energy carrier bands, as well as the onset of non-linear phenomena due to impinging external electromagnetic fields. We are now capable of modelling THz carbon-based emitters/detectors, CNT-enabled traveling wave (TW-CNT) devices, and the carbon-metal transition; we are exploiting novel properties and devices based on frequency multiplication, graphene gyrotropic effects, photoconductive effects.

The Student's activity we will be focusing on:
• Multiphysics Schrödinger/Dirac-based modeling of the electromagnetic-coherent transport phenomena of the graphene/CNT devices. Microwave and Terahertz circuit characterization stemming from the above analysis in a form suitable for design.
• Models of the graphene/CNT-metal transition. Their equivalent circuits models.
• Inclusion of thermal effects in graphene/CNT (e.g. the contact between graphene and silicon dioxide). Their circuit models in system characterization.
• Characterization and validation of electromagnetic/quantum-mechanics properties of carbon nanostructures.
• Electromagnetic characterization of carbon-based foams. Shielding EM interference in chaotic environments.

Main references:
1. "Spatial dispersion effects upon local excitation of extrinsic plasmons in a graphene micro-disk" Davide Mencarelli, Stefano Bellucci, Antonello Sindona, Luca Pierantoni, Journal of Physics D: Applied Physics 48 (2015), 465104
2. "Broadband microwave attenuator based on few layer graphene flakes", Luca Pierantoni, Davide Mencarelli, Maurizio Bozzi, Riccardo Moro, Stefano Moscato, Luca Perregrini, Federico Micciulla, Antonino Cataldo, Stefano Bellucci, IEEE Transactions on Microwave Theory and Techniques, 63 (2015) 2491-2497
3. "Applications of Graphene at Microwave Frequencies", Maurizio Bozzi, Luca Pierantoni, Stefano Bellucci, Radioengineering 24 (2015) 661-669.
4. "Sharp variations in the electronic properties of graphene deposited on the h-BN layer", DG Kvashnin, S Bellucci, LA Chernozatonskii, Physical Chemistry Chemical Physics 17 (2015) 4354-4359
5. "Graphene-based electronically tuneable microstrip attenuator", L Pierantoni, D Mencarelli, M Bozzi, R Moro, S Bellucci, Nanomaterials and Nanotechnology 4 (2014), 4-18

Tutor: Stefano Bellucci (bellucci@lnf.infn.it)

Recommended period: June - July or September - October

1 position

Title: Studies of a scheme for Low EMittance Muon Accelerator with production from positrons on target

Description: We are studying a new scheme to produce very low emittance muon beams using a positron beam of about 45 GeV interacting on electrons on target. This is a challenging and innovative scheme that needs a full design study. One of the innovative topics to be investigated is the behaviour of the positron beam stored in a low emittance ring with a thin target, that is directly inserted in the ring chamber to produce muons. Muons can be immediately collected at the exit of the target and transported to two μ+ and μ− accumulator rings and then injected in muon collider rings. We are focusing on the simulation of the e+ beam interacting with the target, its degradation in the 6-D phase space and the optimization of the e+ ring design to maximize the energy acceptance. We are investigating the performances of this scheme, ring optics plus target system, comparing different multi-turn simulations. A test bean with a 45 GeV positron beam is foreseen in summer to measure the yield and the characteristics of the produced muons.

Tutor: Mario Antonelli (Mario.Antonelli@lnf.infn.it)

Recommended period: July - August

1 position

Title: The RICH detector of the CLAS12 experiment

Description: The CLAS12 experiment is currently running in the Hall B of the Jefferson Laboratory in Newport News (Virginia, USA), using the high energy, high intensity and polarization of the CEBAF electron beam. The physics program of the experiment is broad and covers many aspect of the hadronic physics.

The Frascati group is deeply involved in the study of the nucleon structure by means of semi-inclusive and exclusive reactions.

A new RICH (Ring Imaging CHerenkov) detector has been recently installed inside the CLAS12 spectrometer, with the goal of separating kaons from pions and protons in the momentum range from 2.5 to 8 GeV/c. This will allow the CLAS12 to extend the study of the nucleon structure in kinematic regions otherwise not accessible.

The RICH detector is made by a wall of aerogel tiles as Cherenkov radiator, 391 Multi-Anode photomultiplier tubes to detect the Cherenkov light and a complex mirror system to direct the photons toward the photodetectors. The kaons are separated from the prevalent background of pions and protons by reconstructing the emission angle of the Cherenkov photons and studying the measured hit pattern. A likelihood approach is used to make the final particle identification.

Activity: The student will analyze simulated and real data in order to optimize the parameters of the particle identification algorithm and to study the performance of the detector.

Tutor: Marco Mirazita (marco.mirazita@lnf.infn.it)

Recommended period: June - July

1 position: LHCb

Title: Semileptonic decays of the B_s meson, a tool for New Physics discovery

Description: Description: LHCb is one of the main experiments collecting data at the Large Hadron Collider accelerator. One of its primary goal is to study with high accuracy the properties of b-hadrons that are copiously produced in the proton-proton collisions at LHC.

Measurements performed at B-Factories and LHCb, show an hint of violation of Lepton Flavour Universality (LFU) from the comparison of the B --> D(*) tau nu_tau (semi-tauonic) and B --> D(*) mu nu_mu (semi-muonic) decay widths. If these hints would be confirmed by other measurements it will clearly be a sign of Physics Beyond the Standard Model. It is of paramount importance to study semi-tauonic decays in other b-hadron species both to check the presence of large LFU violation in alternative environments, and to explore different kinematic variables aiming to pin down the kind of New Physics than explains the observed anomalies in the LFU.

We, in the LHCb group in Frascati, are deeply involved in the study of semileptonic decays of B_s mesons. The B_s mesons (constituted by an anti-b quark and s quark instead of an u- or d-quark which constitute a B meson) are interesting because have some advantages compared with the B mesons. A crucial one is that they allow to overcome one the most important background that affects the semi-tauonic decays of the B mesons. This background, which is associated with the decays of orbitally and radially excited charm-meson states, is in fact much less relevant in B_s decays than in B decays. Moreover, semileptonic B_s decays offer many interesting kinematic observables that can be exploited to constrain various plausible New Physics scenarios.

Activities: The student will be deeply involved on key points aspects of the data analysis. Depending on his/her interests and when he/she will be with us, the work can focus on:
- the developments of novel algorithms to control the soft photon efficiency, which is required by some of the measurements we are interested in;
- the optimisation of signal selection and the study of a suitable sample to control the most dangerous backgrounds;
- the improvements of the resolution of the signal kinematic useful for precise measurements of some observables. Some knowledges in computing (e.g. python, C++, root, TMVA,...) are desirable but not mandatory.

LHCb collaboration website for useful general information:
http://lhcb.web.cern.ch/lhcb/
Latest LHCb measurements on semi-tauonic B decays with many interesting links:
http://lhcb-public.web.cern.ch/lhcb-public/Welcome.html#RDst2

Tutors: Marcello Rotondo (marcello.rotondo@lnf.infn.it) and Barbara Sciascia (barbara.sciascia@lnf.infn.it)

Recommended period: 1 June - 31 July, 27 August - 31 October

1 position: LNF Theory Group

Title: Exploring large-x parton distribution functions, from JLab to LHC energies

Description: Description: An accurate knowledge of parton distribution functions (PDF) in the proton has been one of the cornerstones of the physics analysis of data of several colliders, such as the LHC, and will be a key ingredient of any precision study at future accelerators. In fact, hadron-level cross sections are given by convolutions of partonic coefficient functions, which are calculated in perturbative QCD, typically at fixed order in the strong coupling, and parton distribution functions, which are extracted from data. It is well known, however, that finite-order QCD computations are limited in their range of applicability by the occurrence of large logarithms near the boundaries of phase space. Threshold logarithms, in particular, correspond to large values of the Bjorken variable x and are related to soft- or collinear-gluon radiation. In order to enlarge the region in which perturbative QCD can be trusted, these logarithms must be resummed. Using resummed partonic coefficient functions will yield the extraction of companion resummed parton densities from data. Moreover, since these large logarithms are weighted by powers of the strong coupling costant, data at large x and small scales Q2, where the strong coupling is enhanced, such as those collected in electron-proton scattering at JLab (E94-110 and E00-116 experiments), are ideal to determine threshold-resummed PDFs. Nevertheless, at such small scales, one gets close to the Landau pole of the strong coupling constant and would need some prescription to handle it, namely using frozen- or effective-coupling models.

The student will first get familiar with resummed calculations in perturbative QCD and non-perturbative models to deal with the strong coupling constant in the infrared regime. Then, he/she will use JLab data at large x and small Q2 in order to obtain parton distribution functions accounting for threshold resummation in the coefficient functions of electron-proton scattering. The obtained PDFs will be compared with those of sets, such as NNPDF, which do include threshold resummation, but did not consider such small-scale JLab data in the global fits. Finally, by using the DGLAP evolution equations, the student will be able to make predictions for LHC processes wherein large-x resummation is expected to play a role, such as weak-boson or heavy-quark production, for which threshold-resummed coefficient functions are already available.

Tutor: Gennaro Corcella (gennaro.corcella@lnf.infn.it)

Recommended period: June-July, September-October

3 positions: Dark Matter searches - Quantum Mechanics tests - Data Management & Preservation at KLOE-2

The KLOE-2 experiment is currently taking data at the upgraded e+e- DAPHNE collider of the INFN Laboratori Nazionali di Frascati, and by the end of Mach 2018 it will finish the data taking campaign collecting more than 5 fb-1 at the center of mass energy of the phi-meson.
KLOE-2 physics program is mainly focused on KS, eta and eta′ meson rare decays as well as on kaon interferometry, fundamental symmetry tests and physics beyond the Standard Model, including searches for new exotic particles that could constitute the dark matter.
With the end of the data campaign, the KLOE-2 collaboration will focus on data reconstruction and analysis towards Precise Measurements and searches of Physics Beyond the Standard Model.

Title n. 1: Light dark matter searches with the KLOE-2 detector

Description: The possibility to detect light dark matter in the sub-GeV regime through the decay of a light dark sector mediator is a unique opportunity for KLOE-2. A possible signature of the process is the presence of events with a monochromatic photon and missing energy. KLOE-2 collected about 2 fb-1 integrated luminosity with a Single Photon Trigger, with tagged events selected and recorded in a special data stream. Activity of the summer student will include Monte Carlo simulation of the signal, study of advanced algorithms to suppress beam background and analysis of the streamed data. KLOE-2 dataset could also be used to search for the B-boson, a possible mediator of Dark Matter and Standard Model (SM) particles interaction. To this extent more than 5 fb-1 of data are available. The B-boson decay mimics the Standard Model known decays, therefore representing a challenge in analysis techniques to achieve a precise measurement of the upper limit on the coupling between dark and SM sectors in the sub-GeV mass range. The summer student will participate in the ongoing analysis, contributing to the implementation of new approaches in calculating Upper Limits and applying Bayesian methods. Basic knowledge in C++ and ROOT framework of CERN is welcome.

Tutors: Enrico Graziani (Enrico.Graziani@lnf.infn.it) and Elena Perez del Rio (Elena.PerezDelRio@lnf.infn.it)

Recommended period: September-October

Title n. 2: Towards testing Quantum Mechanics with neutral kaons at KLOE-2

Description: The entanglement in the neutral kaon pairs produced at the DAPHNE phi- factory is a unique tool to test discrete symmetries and the basic principles of quantum mechanics.
The decay phi → KSKL → π+π−π+π− will be used among the others, significantly improving present results exploiting the insertion of a dedicated GEM-based tracking detector.

Both neutral kaons will decay within few cm from the interaction point, therefore detector performance in terms of spatial resolution and its stability along data taking are essential to better isolate signal selection and improve signal to background rejection.
The student will participate in the development of dedicated algorithms to select 4-pion final states and in the measurement of tracking and vertexing performance by studying event topologies and signatures in the KLOE-2 detector, using as one of the figures of merit the stability of Ks lifetime measurement.
Basic programming skills are required.

Tutors: Antonio Di Domenico (antonio.didomenico@roma1.infn.it) and Paolo Gauzzi (Paolo.Gauzzi@roma1.infn.it)

Recommended period: June - July

Title n. 3: Data Management & Preservation at KLOE-2

Description: Students with a background in Physics and/or Computer Science are warmly welcome to join the KLOE-2 Offline Group to participate in the development of new monitoring tools, code optimization and algorithm design as well as data management, such as data preservation and storage.

Familiarity with programming languages like C++, Python, FORTRAN and Perl, together with different debugging tools and High Energy Physics frameworks, like ROOT from CERN, are desirable.
Particularly, we offer the possibility of joining the Offline Group in designing and implementing new algorithms more adapted to a new target language and newly installed KLOE-2 computing resources.
This gives a unique opportunity to improve/learn new programming skills and experience team work within a collaborative and friendly environment.

Tutors: Giuseppe Fortugno and Elena Perez del Rio (Elena.PerezDelRio@lnf.infn.it)

Recommended period: September-October

The application form is available on the Summer Exchange Program homepage.

LOCAL EXCHANGE PROGRAM CONTACTS:

Personnel Office:

Gianluca Dalla Vecchia

Scientific coordination:
Catalina Curceanu (coordinator)
M. Cristina D'Amato (secretary)
Phone +39-06-94032373

author: mcd