CERN - Ukraine 2024: "Past - Present – Future" Conference, Kyiv Ukraine, May 28-29, 2024

May 28, 2024, 9:00 AM → May 29, 2024, 11:27 PM Europe/Kyiv

This event will be organized in a framework of the CERN’s 70th Celebration Programme, highlighting CERN achievements over the past years, addressing future projects at CERN and worldwide, as well as contributions of Ukrainian scientists to these endeavors.

Note that the timetable is given in Kyiv time, which is 1 hour ahead of CERN. 

Abstract submission is open till 22 April 2024 at 23:59 (Europe/Kyiv).

Registration is open till 8 May 2024 at 23:59 (Europe/Kyiv).

Tuesday, May 28

10:00 AM → 12:00 PM Opening Plenary Session: CERN 70 Years and Ukraine 30+ Years in CERN

Convener: Nicolas Berger (Centre National de la Recherche Scientifique (FR))

10:00 AM Welcome from CERN Director-General

Speaker: Fabiola Gianotti (CERN)

Gianotti.mp4

10:10 AM Welcome from First Deputy Minister at the Ministry of Education and Science of Ukraine

Speaker: Yevhen Kudriavets (Ministry of Education and Science of Ukraine)

IMG_4037.MOV

10:20 AM Welcome from the President of the National Academy of Science of Ukraine

Speaker: Prof. Anatoly Zagorodny (National Academy of Sciences of Ukraine)

Zagorodny.mp4

10:30 AM CERN Highlights and Future Plans

Speaker: Joachim Josef Mnich (CERN)

JM CERN Highlights.pdf

JM CERN Highlights.pptx

Mnich.mp4

11:00 AM ECFA Highlights

Speaker: Paris Sphicas (CERN/Athens)

2024-05-27-ECFA-Report-Ukraine.pdf

Sphicas.mp4

11:20 AM CERN70 Celebration Events - Inspiring the Future

Speaker: Luciano Musa (CERN)

Musa.mp4

11:40 AM Ukraine - СERN: the Way to Cooperation

Speakers: Boris Grynyov (Kharkov State University (KSU)), Boris Grynyov (National Academy of Sciences of Ukraine (UA))

CERN_UA.pdf

CERN_UA.pptx

Grynyov.mp4

12:00 PM → 1:00 PM Session I

Convener: Nicolas Berger (Centre National de la Recherche Scientifique (FR))

12:00 PM Highlights from ATLAS Experiment

Speaker: Andreas Hoecker (CERN)

ATLAS-Highlights-UkraineCERN-28May2024.pdf

Hoecker.mp4

12:30 PM Highlights from CMS Experiment

Speaker: Patricia McBride

CMS_2024-05-28.pdf

McBride.mp4

1:00 PM → 2:00 PM Lunch Break

2:00 PM → 4:00 PM Highlights from CERN LHC Experiments

Convener: Andriy Boyaryntsev (National Academy of Sciences of Ukraine (UA))

2:00 PM Highlights from LHCb Experiment

Speaker: Vincenzo Vagnoni (INFN Bologna (IT))

CERN 70 Ukraine 2024.pdf

Vagnoni.mp4

2:30 PM Highlights from ALICE Experiment

Speaker: Marco Van Leeuwen (Nikhef National institute for subatomic physics (NL))

20240528_ALICE_highlights_CERN70_Ukraine.pdf

van_Leeuwen.mp4

3:00 PM Interference effects in the ionization loss of high-energy particles. Theory and CERN SPS experiments

When a charged particle moves in a medium it loses part of its energy on ionization and excitation of atoms. This part is known as ionization energy loss. Experimentally, it is often convenient to measure not the total value of the particle ionization loss, but just a part of it due to collisions with relatively small momentum transfers (distant collisions), which is known as restricted ionization loss (RIL). When a high-energy particle enters a target from vacuum, a transformation of the electromagnetic field around the particle occurs in a thin boundary layer of the target, which leads to the change of RIL along the particle path. There has been an attempt to investigate such a boundary effect at SPS accelerator at CERN [1]. Though, due to a large target thickness, almost no effect has been observed. In the present report we propose a different experiment in which an analogous effect is expected to be significant due to the particle's field transformation not in the medium, but in a vacuum. We consider a process in which a high-energy electron consecutively traverses two targets situated on some distance $l$ from each other: a thick upstream one and an ultrathin downstream one. It is shown that evolution of the particle's field after its passage of the upstream target should result in a considerable modification of the particle RIL in the downstream target [2, 3] and its dependence on $l$. Such an effect results from the inteference of the electron's proper field and the field of transition radiation, which evolves as a result of the particle passage through the upstream target. Such interference makes the electron `half-bare', which results in the change of its RIL. For electron energies of about 100 GeV, achievable at SPS, the discussed effect can take place within a macroscopically large distance between the tagrets, of the order of several tens of meters.

Another type of interference effect in RIL, known as the Chudakov effect, takes place for high-energy electron-positron pairs. It results from the destructive interference (mutual screening) of the electron's and positron's proper electromagnetic fields in the vicinity of the pair creation point in a medium, and leads to suppression of the pair RIL in this region. In [4, 5] the first accelerator-based experimental investigation of this effect at SPS has been reported. In this experiment the most probable value $E_{MP}$ of the pair RIL in thin silicon detectors has been measured. The results were noticeably different from the predictions of all existing theories of Chudakov effect (which describe the average value $E_{AV}$ of the pair RIL in the target per unit path). In the present work we obtain the probability distribution function for the value of the pair RIL in a thin target and calculate the quantity $E_{MP}$ [6]. It is shown that the Chudakov effect of RIL suppression is stronger manifested for $E_{MP}$ than for $E_{AV}$ and the developed theory better coinsides with the experimental results [4, 5] than the mentioned theories for $E_{AV}$.

1. K.K. Andersen et al. Nucl. Instrum. Methods B, 268 (2010) 1412.
2. N.F. Shul’ga, S.V. Trofymenko, Phys. Lett. A, 376 (2012) 3572.
3. S.V. Trofymenko, N.F. Shul’ga, Phys. Rev. Accel. Beams, 19 (2016) 112801.
4. T. Virkus et al., Phys. Rev. Lett. 100
   (2008) 164802.
5. H.D. Thomsen, U.I. Uggerhøj, Nucl. Instrum. Methods B 269 (2011) 1919.
6. S.V. Trofymenko, Eur. Phys. J. C, 83 (2023) 32.

Speaker: Dr Sergii Trofymenko (NSC 'Kharkiv Institute of Physics and Technology')

Trofymenko.mp4

3:20 PM NSC KIPT participation in the CMS experiment: the history and present activities

The National Science Centre “Kharkiv Institute of Physics and Technology” (NSC KIPT) has been participating in the CMS experiment since the early 1990’s. The main efforts were then focused on R&D studies aimed at searching for an appropriate scintillation material for the CMS hadron calorimeter (HCAL), which was in development. The Institute was also involved in construction of HCAL prototypes and their beam-testing at CERN, as well as in computer simulations of the CMS hadronic calorimetry in general. This was followed by the mass production of endcap HCAL scintillator tiles in Ukraine, in which KIPT performed the tile quality control based on light output measurements. Upon successful completion of this work in the early 2000s, preparations started at the NSC KIPT for participation in processing of CMS data – samples of proton-proton collisions to be obtained at the LHC. Based on computer simulations, the possibility was estimated to observe a Higgs boson with a mass above the on-shell ZZ decay threshold in the CMS experiment. Also, a computing facility was constructed, which became the first Ukrainian WLCG site and then (in 2009) commissioned (under the name of T2_UA_KIPT) as the Tier-2 (T2) centre of the CMS grid infrastructure. After the LHC startup, more than 20 PB of CMS experimental information have been transferred to the T2_UA_KIPT site for processing, with a high level of the site stability and reliability being provided. At present, in addition to the computing infrastructure of the experiment, the NSC KIPT is also involved in activities on the support and upgrades of the CMS hadron calorimetry. In particular, the measurements were carried out at the NSC KIPT that illuminated the strong dose-rate dependence of the light output reduction in plastic scintillators under irradiation and thus provided an explanation for the “premature” signal degradation in the endcap HCAL observed upon completion of the LHC Run 1. An experimental study of the radiation resistance of various scintillation materials is also being carried out in order to assess prospects for their future usage in either the CMS or other high-energy physics experiments. Another important subject of our activities within the CMS is participation in the physics analysis of the data obtained in the experiment. Last years, this work has been mainly focused on searching for supersymmetry signals based on the analysis of proton-proton collision samples recorded in the LHC Run 2 through selection of the events with a large missing transverse momentum and two high transverse-momentum leptons.
The work was supported in part by grants of the NAS of Ukraine (NASU) within the targeted research program “Collaboration in advanced international projects on high-energy and nuclear physics” and the “NASU informatization program”.

Speaker: Leonid G. Levchuk (NSC Kharkiv Institute of Physics and Technology, 61108 Kharkiv, Ukraine)

KIPT_at_CMS_2024.pdf

Levchuk.mp4

3:40 PM INVESTIGATION OF RESISTANCE TO HIGH-VOLTAGE VACUUM BREAKDOWN OF ION AND PLASMA-MODIFIED MATERIALS FOR ACCELERATOR STRUCTURE OF THE CLIC COLLIDER

V.A. Baturin, O.Yu. Karpenko, O.Yu. Roenko, S.O. Yeryomin, V. Yu. Storizhko

Institute of Applied Physics, National Academy of Sciences of Ukraine,
58 Petropavlovskaya St. Sumy, 40030 Ukraine, baturin49@gmail.com

The European Centre for Nuclear Research (CERN) is developing and constructing the Compact Linear Electron Collider (CLIC), which is planned to reach an energy of ~4.3 TeV in the centre of mass system. In the high-frequency structures of this collider, it is planned to achieve accelerating gradients of 100 MV.
An extremely important task is to conduct comprehensive research on the choice of material for the manufacture of elements of the accelerating structures of the CLIC collider, and to develop a technology for processing its surface, which would make it possible to achieve the required values of accelerating gradients.
The Institute of Applied Physics of the National Academy of Sciences of Ukraine proposed, developed and tested plasma and ion-beam methods for modifying the surface layers of copper samples, which increase the resistance of their surface layer to vacuum breakdowns and reduce the likelihood of their occurrence.
It is shown that such modification of copper surface layers can significantly increase the resistance of copper samples to high-voltage breakdowns.

Speaker: Vladimir Baturin

Yeryomin.mp4

4:00 PM → 4:30 PM Coffee Break

4:30 PM → 6:30 PM Session III

Convener: Mark Gorenstein

4:30 PM BEAUTY, CHARM and STRANGENESS of LHCb. (View in Ukraine from the 70 years tower of CERN)

Some results are presented on the activities of scientists of the Institute for Nuclear Research NAS Ukraine (KINR) within the framework of international collaborations LHCb, MEDIPIX and ENLIGHT (CERN, Geneva),
The LHCb Collaboration functions for almost 30 years with the main goal to study the CP violation, in heavy flavor hadrons (beauty, charm) as one of the possible reasons for asymmetric composition of the Universe.. Ukrainian scientists have contributed into building the Silicon tracker as well as Beam & Background monitoring systems developed and built at KINR. Data obtained in the experiment (colliding as well as fixed target mode), on the decay of heavy hadrons allowed to measure their mass, lifetime, oscillation frequencies, ratio of branches of decay, etc. with the most accurate precision or to observe/dicover a phenomenon for the first time in the world (penta quarks, rare decay modes, CPV etc.). Detailed analysis is ongoing for the properties of neutral strange hadrons (V0) produced in p-p and p-Pb collisions at 5.02 and 8.16 TeV. In particular, nuclear modification factors demonstrate interesting dependence on the multiplicity of the final states. By far non-trivial results were obtained in the data analysis of ultra-peripheral production of charmonium in Pb-Pb collisions at the energy of 5 TeV. Looking forward to the running LHCb experiment at the era of HL-LHC with instantaneous luminosity increased by two orders of magnitude compared to the initial one in RUN1. KINR scientists contribute into the LHCb UPGRADE II activity, developing a monitoring system for the on-line observation of the luminosity region.
In terms of technology transfer,an application of micropixel detectors was fulfilled in frames of activity within the MEDIPIX and ENLIGHT Collaborations (CERN), International Associated Laboratory LIA IDEATE (France — Ukraine). Micro-detector systems, including one micrometer thick metal microstrip detectors developed at KINR, have been successfully tested at the Heidelberg Ion Therapeutic Center (HIT, Heidelberg, Germany). "Electronic focal planes” based on micro-pixel (Timepix) detectors have essentially improved performance of the laser mass-spectrometer (IAP NASU, Sumy) as well as Roentgen diffractometer (IPM NASU, Kyiv). For the first time in experiments on low energy nuclear physics micropixel detectors (Timepix) were implemented in correlative studies of the aneutronic fusion reaction, presumably prospective source of the clean production of the energy. The technique of high energy physics experiments poses a challenge to the most modern technologies and encourages the scientific and technological progress of mankind. This area of activity requires the involvement of new intellectual forces, including ones from Ukraine and CERN.
This project has received funding through the EURIZON project, which is funded by the European Union under grant agreement No.871072. The authors acknowledge financial support by the EIRENE grant (MPG, Germany) as well as in frames of the Targeted NAS Ukraine Programme "Participation in the latest international projects in high-energy and nuclear physics".

Speaker: Prof. Valery Pugatch (Institute for Nuclear Research, National Academy of Sciences of Ukraine (UA))

Pugatch.mp4

4:50 PM Software development for PLUME detector at LHCb experiment

For luminosity measurement at LHCb, a key component is the luminosity detector, which typically employs silicon sensors or other types of radiation detectors to measure the rate of collisions between particles, such as protons, in the Large Hadron Collider (LHC) beams. These detectors are often placed around the interaction region to capture particles produced in the collisions.

A new luminosity counter called PLUME (Probe for LUminosity MEasurement) was installed during LS2 to perform this task. It consists of 48 PMTs with quartz windows, that are triggered by a Cherenkov light generated by a passing charged particle.

The team from Taras Shevchenko National University of Kyiv was involved in this project since the early stages of the development. Several students performed critical tasks such as the development of the Monte-Carlo simulations to assess the detector performance and general concept, integration of the simulation to the LHCb software stack, development of the encoding and decoding algorithms for the DAQ, proposal, and creation of novel techniques for timing measurement.

Speaker: Vladyslav Orlov (Taras Shevchenko National University of Kyiv (UA))

Orlov.mp4

5:10 PM ISMA – CERN collaboration in the field of oxide scintillators

The collaboration between ISMA and CERN began in the early 1990s when ISMA (then part of the Institute for Single Crystals), played a pioneering role in the development of lead tungstate (PbWO4), a scintillator implemented in both in CMS and ALICE experiments at the Large Hadron Collider. Works by L. Nagornaya et al. demonstrated the feasibility of achieving an extremely fast scintillation response and growing highly uniform large PbWO4 crystals with high radiation tolerance [1].
Since over 30 years, the collaboration continued within the Crystal Clear collaboration and the SCINT community initialized in 1992 for the needs of new inorganic scintillators for future HEP experiments. More recently collaboration between CERN and ISMA on R&D on scintillators was reinforced by many European projects: With the INTELUM H2020 project (2015-2019, Grant Agreement n°644260), which focused on the fabrication technology of garnet scintillation fibers for high-granularity calorimeters. Ce-doped Y3Al5O12 (YAG:Ce) and Lu3Al5O12 (LuAG:Ce) fibers with 1-2 mm cross-section and lengths of up to 55 cm were produced using the micro-pulling-down method in collaboration with ILM. The luminescence attenuation length in LuAG:Ce fibers reached 1 m, meeting transparency requirements [2]. Meanwhile, although the micro-pulling-down technology could provide ready-to-use fiber-shaped crystals without post-growth mechanical treatment, the growth of bulk crystals and cutting them into fibers proved to be a more reliable approach for producing many thousands of fibers required for large-scale experiments at colliders.
Materials development for fast-timing applications has started with the COST Action (Fast, COST TD1401) and continues in the ongoing Horizon Europe TWISMA project (Grant Agreement n°101078960), involving ISMA, CERN, and ILM, and focusing on bulk crystals produced by the Czochralski method. It addresses rare earth garnets such as YAG:Ce and GAGG:Ce with accelerated luminescence rise/decay times and enhanced time resolution. These materials are considered as potential candidates for the upgrade phase of the inner part of the electromagnetic calorimeter of LHCb experiment [3]. For this purpose, very fast radiation hard scintillators are required to eliminate any pileup of signals at the frequency of particle collision of 25 ns. Various codoping schemes of garnet crystals are being verified to achieve a balance between cerium luminescence quenching, providing a decay faster than the Ce3+ intrinsic lifetime, and reasonable light yield. Another focus of TWISMA is crystals for dual-readout detectors for simultaneous and independent registration of scintillation and Cherenkov light at future colliders [4]. Bi4Si3O12 and Bi4(Ge1-xSix)3O12 have been proposed [5] as monolithic crystals capable of registering both scintillation light emitted in the visible band and providing a wide transparency window in the UV at >290 nm for Cherenkov light registration.

[1] L. Nagornaya, V. Ryzhikov, Proc. of International Workshop on Heavy Scintillators for Scientific and Industrial Applications: Crystal 2000 (1992), 367-374.
[2] V. Kononets, K. Lebbou, O. Sidletskiy, Yu. Zorenko, M. Lucchini, K. Pauwels, and E. Auffray, M. Korzhik and A. Gektin (eds.), In: Engineering of Scintillation Materials and Radiation Technologies, Springer Proceedings in Physics 200 (2017), pp. 114-128.
[3] CERN-LHCC-2021-012 LHCb TDR 23, 24 February 2022, ISBN 978-92-9083-623-0.
[4] M.T. Lucchini, W. Chung, S.C. Eno, Y. Lai, L. Lucchini, M. Nguyen and C.G. Tully, M.T. Lucchini, et al., J. Instrum. 15 (2020) P11005.
[5] R. Cala’, N. Kratochwil, L. Martinazzoli, M.T. Lucchini, S. Gundacker, E. Galenin, I. Gerasymov, O. Sidletskiy, M. Nikl, E. Auffray, NIM. A 1032 (2022) 166527.

Speaker: Oleg Sidletskiy (Institute for Scintillation Materials, National Academy of Sciences of Ukraine (UA))

Sidletskiy.mp4

5:30 PM Low material budget aluminium-polyimide adhesiveless interconnection elements for detectors for LHC and future colliders

One of the key achievements within last decade in creating vertex detectors for upgrade existing and creating new detectors for physics experiments is developing and using novel thin silicon novel thin Monolithic Active Pixel Sensors (MAPS) e.g. ALPIDE MAPS developed by ALICE collaboration for Upgraded Inner Tracking System (ALICE ITS2). Using such thin (~50um thick) silicon sensors allows to obtain unprecedented low material budget of 0.05-0.1%X0 per layer.
Meanwhile, for successful realization of low material budget detector modules also need to be chosen and used reliable and robust interconnection technique and low budget materials for realization of interconnection elements. Taking into account features of existing technologies, materials and approaches one of optimal option is using single- and multilayered printed circuit flexible microcables and boards based on adhesiveless aluminium-polyimide foiled dielectrics. As an interconnection techniques ultrasonic welding of aluminium ribbon leads can be used (Single-point TAB technique, SpTAB).
Using special ultralight microcables (so-called ,,chipcables,,) allows to perform functional testing MAPS that results to ensure using only fully tested and high-quality sensors for further assembling detector modules (approach is implementing in pixel layers for ALICE FoCal).
Abovementioned materials and approaches also might be used for novel extremely low budget detector layers based on thin curved/bent stitched MAPS. Using such materials and approaches allow to perform connecting flexible interconnection elements to the sensor and then perform their bending to required radius (prototypes of ALICE ITS3 single chip assemblies created and successfully tested).
As further development for realization interconnection elements for detector layers new adhesiveless aluminium-polyimide materials with thin (10um) and thick (200um) conductive aluminium layers for low budget modules and for modules with requirements concerning low voltage drop respectively are developed.

Speaker: Ihor Tymchuk (National Academy of Sciences of Ukraine (UA))

Tymchuk.mp4

5:50 PM The SHiP experiment and hunt for heavy neutral leptons

The SHiP experiment is a recently approved beam-dump experiment aimed at searching for light long-lived particles with astonishing 6e20 protons on target. I will discuss the status of the experiment and its prospects in finding new physics and, in particular, testing the relation of newly seen particles to the Beyond the Standard Model problems, with a focus on heavy neutral leptons.

Speaker: Oleksii Mikulenko (Leiden University (NL))

Mikulenko.mp4

SHiP_CERN_Ukraine_28_05_2024.pdf

6:10 PM Studying the influence of the edge effects on the energy resolution of the novel GRAiNITA calorimeter

This abstract describes the results of the Geant4 simulation done by participants in the Group of Taras Shevchenko National University of Kyiv in LHCb collaboration in close coworking with researchers at Université Paris-Saclay, CNRS/IN2P3, IJCLab, France.

The calorimeters play an essential role in high-energy physics detector setups. One of the widely used nowadays calorimeter techniques is the so-called Shashlyck calorimeter, which contains successive layers of absorber material, with high density and atomic number, and layers of scintillator material. Scintillation light is proportional to the deposited energy, it is gathered by WLS fibres and carried to the photomultiplier. The conventional Shashlik detectors provide a resolution of about R~$10\%/ \sqrt{E}$

The novel calorimeter type GRAiNTIA was proposed as an advanced version of Shashlik calorimeters. The key difference of this is that the absorber and scintillator are combined in one volume in scintillation grand and high-density liquid as an absorber. The expected energy resolution of such a detector type is about R~$2\%/ \sqrt{E}$

To evaluate the energy resolution of the detector, the detector prototype, of dimensions 168x168x400 mm was simulated with the Geant4 toolkit. The prototype was simulated as a single volume with a single material of radioactive properties that match the mixture of ZnWO$_4$ grains and heavy liquid. The detection energy loss caused by the escape of secondary particles from the detector was calculated from the simulation.

The result of the simulations for 25 GeV gamma quants shows, that for most of the volume (the inner volume which is more than 14 mm off from the detector edge), the expanded energy has a fixed value and its uncertainty stays below 1% of the induced particle energy.

Further studies show that in case the primary hit was close to the detector edge, the escaped energy is correlated with the deposited one. Thus the escaped energy could be predicted, as a consequence, the uncertainty of the escaped energy can be decreased to the value below 1%.

Studies of sources of energy escape indicate that there is always uncertainty due to exit-facet escape, and this part dominates if the primary hit is in the inner part of the detector. Close to the edge of the detector, mean uncertainty in energy escape is due to side-facet escape.

For studies of the effects of shower development on the exit-escape energy, the pre-shower (energy deposited in first 64 mm in detector volume along primary particle movement) was calculated. The result of the simulation for 25 GeV gamma shows that most of the events with exit-escape energy larger than 250 MeV got less than 20 MeV in the pre-shower.

Speaker: Denys Klekots (Taras Shevchenko National University of Kyiv (UA))

Klekots.mp4

Slides.pdf

6:30 PM → 8:00 PM Conference Reception

Wednesday, May 29

9:00 AM → 11:00 AM Session IV

Convener: Boris Grynyov (National Academy of Sciences of Ukraine (UA))

9:00 AM LIA France-Ukraine in the CERN Projects

Speaker: Sergey Barsuk (Université Paris-Saclay (FR))

Barsuk.mp4

CERN_UA_LIA_SB_a.pdf

9:20 AM Implementation of the ECFA Detector R&D Roadmap and CERN - DRD1 Collaboration

Speaker: Dr Maksym Titov (IRFU, CEA Saclay, Université Paris-Saclay (FR))

2024_05_KYIV_CERN-UKRAINE-CONFERENCE_ECFA-RD-ROADMAP_DRD1-COLLABORATION_29052024.pdf

2024_05_KYIV_CERN-UKRAINE-CONFERENCE_ECFA-RD-ROADMAP_DRD1-COLLABORATION_29052024.pptx

Titov.mp4

9:40 AM CERN- Ukraine: Junior Academy of Science of Ukraine

Speaker: Oleksandr Yurov (National Center Junior Academy of Science of Ukraine)

REPORT-Dovgii-Yurov-29-05-2024.pdf

REPORT-Dovgii-Yurov-29-05-2024.ppt

Yurov.mp4

10:00 AM Studies of the LPM and TSF effects at CERN

In 1953, Landau and Pomeranchuk showed [1] that multiple scattering of ultrarelativistic electrons on atoms of the medium can lead to suppression of bremsstrahlung in the soft part of the spectrum compared to the predictions of the Bethe-Heitler theory. A quantitative theory of this effect was later developed by Migdal [2]. The region of the radiation spectrum in which Landau-Pomeranchuk-Migdal (LPM) appears rapidly increases with increasing particle energy and in the region of TeV electron energies and above significantly affects almost the entire radiation spectrum, leading to a significant reduction in radiation losses of particles. As a result, such an important quantity as the radiation length begins to depend on the particle energy, which must be considered when designing particle detectors and radiation shielding at future high-energy lepton colliders. For this reason, at the end of the last century, a special experimental study of this E-146 effect was carried out at the SLAC accelerator to test the predictions of the Migdal theory of the LPM effect and the subsequent inclusion of this effect in computer codes such as GEANT and others [3]. However, when analyzing the experimental data obtained, it turned out that both the Migdal theory and the Bethe-Heitler theory do not fully describe the behavior of the emission spectra. Particularly significant discrepancies were observed for relatively thin targets [3]. Including into consideration the dielectric mechanism of radiation suppression (the Ter-Mikaelian effect [4]) and transition radiation did not eliminate the indicated discrepancy. The special behavior of the emission spectra in the case of a thin target was predicted earlier in [5, 6]. A quantitative theory of the effect of radiation suppression in a thin layer of substance was developed in [7] and are described in detail in the review [8]. A detailed experimental study of the discussed effects, with special attention to radiation in a thin target, was carried out by the NA63 collaboration in the 2000s at the CERN SPS accelerator [9]. After quantitative confirmation of theoretical predictions [7], the effect of radiation suppression in a thin layer of substance was called the Ternovskii-Shul’ga-Fomin effect or TSF effect [9]. Despite the fact that both LPM and TSF effects are caused by the influence of multiple scattering on the radiation process, their manifestations in the spectral and angular distributions of radiation, as well as in the thickness dependence of the radiation intensity, are radically different [6-10]. All these features of the bremsstrahlung process at high energies, when LPM and TSF effects begin to play a decisive role in the formation of bremsstrahlung, must be considered when designing future lepton colliders and detection systems for them. Analogues of the LPM and TSF effects should also take place in QCD during the interaction of quarks and gluons.

[1] Landau L.D. and Pomeranchuk I.Ya. Dokl. Akad. Nauk SSSR 92 (1953) 535, 735.
[2] Migdal A.B. Phys. Rev. 103 (1956) 1811.
[3] CERN Courier 34 (1994) #1; Klein S., Rev. Mod. Phys. 71 (1999) 1501.
[4] Ter-Mikaelian M.L., Dokl. Akad. Nauk SSSR 94 (1954) 1033.
[5] Ternovskii F.F., Sov. Phys. JETP 12 (1961) 123.
[6] Shul’ga N.F. and Fomin S.P., JETP Lett. 27 (1978) 117; Phys. Lett. A 114 (1986) 148.
[8] Akhiezer A.I., Shul’ga N.F. and Fomin S.P. Landau-Pomeranchuk-Migdal Effect. Cambridge Scientific Publishers, 2005, 215 p.
[9] Thomsen H.D. et al., Phys. Lett. B 672 (2009) 323; Phys. Rev. D 81 (2010) 052003.
[10] Fomin A.S., Fomin S.P. and Shul'ga N.F., Nuovo Cimento 34C (2011) 45.

Speaker: Dr Sergii Fomin (NSC KIPT)

Fomin.mp4

10:15 AM Experimental investigation on steering of ultrarelativistic particle beams through axially oriented bent crystals

An investigation into the stochastic deflection of high-energy charged particles in a bent crystal was conducted at the extracted lines of the CERN Super Proton Synchrotron. Specifically, we examined the mechanism of relaxation of axially confined 400 GeV/c protons to planar channeling in a bent crystal. The experimental results were critically compared to computer simulations and analytical estimations, demonstrating a good agreement. We conclusively identified a necessary condition for the utilization of axial confinement or its relaxation for particle beam manipulation in high-energy accelerators. We demonstrated that with a short bent crystal, aligned with one of its main axes to the beam direction, it is possible to realize either a total beam steerer or a beam splitter with adjustable intensity.
We also investigated the deflection efficiency under axial confinement of 120 GeV/c electrons and positrons as a function of crystal orientation, the choice of the bending plane, and the charge sign. In particular, we identified the optimal orientations of the crystal's bending plane, which enable the deflection of the largest number of charged particles using a bent crystal in axial orientation.

Speaker: Laura Bandiera (Universita e INFN, Ferrara (IT))

Bandiera.mp4

Ukranian-CERN-29may2024.pdf

10:30 AM Study of Orientation Effects in the Passage of High-Energy Particles through Straight and Bent Crystals

Crystalline materials differ from amorphous ones in the presence of periodicity in the arrangement of atoms. This periodicity leads to the possibility of observing orientation effects when high-energy charged particles pass through crystals. Such effects become possible when the angle between the particle's momentum and the crystalline atomic axis or plane becomes small. In this case, the particle coherently scatters on neighboring atoms of the crystal, leading to an enhancement of the effective interaction potential. If the crystal is bent, such coherent scattering allows to deflect fast charged particles from their original direction of motion. This makes bent crystals an effective tool for solving tasks such as particle extraction from cyclic accelerators and improving the collimation of charged particle beams in accelerators. This report presents the results of studies on orientation effects when fast charged particles pass through crystals.

Speaker: Dr Igor Kyryllin (NSC 'Kharkiv Institute of Physics and Technology')

Kyryllin.mp4

10:45 AM Unexpected large isospin breaking in high-energy collisions

It is well known that isospin symmetry is fulfilled to a good approximation in strong interactions, as confirmed in low-energy scattering experiments and in mass spectra of both light and heavy hadrons. In collisions of nuclei with an equal number of protons and neutrons, isospin symmetry imposes that the number of produced charged kaons should equal the number of neutral ones. The NA61/SHINE experiment at CERN recently reported an excess of charged over neutral kaon production in high-energy nucleus-nucleus collisions. Here, we argue that the measured charge-to-neutral kaon ratio of about 1.2 indicates an unexpectedly large violation of isospin symmetry. Using well-established models for hadron production, we demonstrate that known symmetry-breaking effects and the initial nuclei containing more neutrons than protons lead only to a small (few per cent) deviation from unity at high energies. Thus, they cannot explain the measurements.

Speaker: Prof. Francesco Giacosa (Kielce University)

Giacosa_CERN_UKRAINE_2024.pdf

Giacosa.mp4

11:00 AM → 11:30 AM Coffee Break

11:30 AM → 12:15 PM Session V

Convener: Tetiana Hryn'ova (Centre National de la Recherche Scientifique (FR))

11:30 AM Fixed-target experiments at LHC with bent crystals. MDM measurement of short lived particles.

Utilisation of bent crystals at LHC opens up a unique possibility of direct measurement of electromagnetic dipole moments (MDM and EDM) of short lived particles. We present a detailed sensitivity study showing the feasibility of such experiments at the LHC in the coming years. The latest experiments on deflecting efficiency of crystals at SPS and LHC suggest that the MDM of charmed baryon could be measured at LHC within two years, and about ten years of operation is needed to reach the current (from indirect measurement) precision on MDM of tau lepton.

Speaker: Alex FOMIN (IJCLab , Universite Paris-Saclay, IN2P3/CNRS)

2024_CERN-UA_MDM_with_crystals_Alex_Fomin.pdf

Alex_Fomin.mp4

11:45 AM Spin-correlation effects in tau-lepton pair induced by anomalous magnetic and electric dipole moments

Anomalous contributions to the magnetic and electric dipole moments of the tau lepton have brought renewed interest in the development of new CP violating signatures in tau-pair production at Belle II, and at higher energies of the Large Hadron Collider and the Future Circular Collider. We discuss spin correlations in the tau- tau+ pair produced in electron-positron and quark-antiquark annihilation, as well as in photon-photon collision. Effects of anomalous dipole moments are introduced on top of calculation of these processes in the Standard Model. The tau decays are simulated along with radiative corrections, in particular, electroweak box WW- and ZZ-exchange diagrams are taken into account.

Speaker: Alexandr Korchin (NSC Kharkiv Institute of Physics and Technology, Kharkiv, Ukraine)

Korchin.mp4

Talk_Korchin_CERN-Ukraine.pdf

12:00 PM Fluctuations and local charge conservation

Transverse momentum correlations were recently measured by the ALICE collaboration at the LHC. A long-range structure in terms of relative pseudorapidity of particle pairs is observed. This may imply some signal of the initial state owing to the shear spread of the correlation. However, the fluctuations inside a thermally equilibrated medium have to be taken into account, serving as motivation for this letter. Using lattice Quantum Chromodynamics (lQCD) constraints, we predicted the development and spread of balancing correlations caused by energy-momentum conservation. Simultaneously, we propagated the initial correlation using hydrodynamics to estimate its effects. Our findings suggest that the resulting correlation, known as the ridge, is sensitive to both fluctuations in the equilibrated medium and the pre-equilibrium stage. This can provide important insight into the early stages of the collision.

Speaker: Mr Oleh Savchuk (Frankfurt Institute for Advanced Studies)

Savchuk.mp4

12:15 PM → 1:15 PM CERN-Ukraine Discussion Session: Inputs to the European Strategy Update and Future of CERN-Ukraine Research Activities

Convener: Tetiana Hryn'ova (Centre National de la Recherche Scientifique (FR))

12:15 PM Roundtable Discussion in English and Ukrainian

Speakers: Prof. Anatoly Zagorodny (National Academy of Sciences of Ukraine), Prof. Christoph Schaefer (CERN)

UA AMS benefits.pdf

UA AMS benefits.pptx

1:15 PM → 2:00 PM Lunch Break

2:00 PM → 4:15 PM Session VI

Convener: Oleksandr Sorokin

2:00 PM PHYSICS BEYOND THE STANDARD MODEL: ACHIVEMENTS AND PROSPECTS

The application of continuous and discrete groups to the theory of nuclei [1], elementary particles [2-4], in the theoretical physics of high energies leads to the need of systematization of knowledge and methods to obtain new information about phase transitions at high energies. Attempts to find a theory of the experiment on the scale of QCD led to the discovery of String Theory. The development of superstring theory as applied to cosmology led to the concept of the "Universe on brane". D-brane theory asserts that gravity and quantum mechanics are integral principles of the construction of the Universe. D-branes are used to solve three serious problems of the Big Bang: flatness problem; the problem of the horizon; the dark energy problem. The application of a complex approach in the study of new physics at high energies is an effective way of studying all four types of interaction within the framework of the theory of D-branes and superstrings, which are necessary for solving the current problems of modern theoretical and experimental physics.
The purpose of the work is to clarify the properties of physical objects such as vibrational modes of superstrings located between D-branes for purposeful search on modern accelerators in the form of Kaluza-Klein modes of gauge particles, microscopic black holes and other exotic particles. The study of black holes through the prism of the geometry of extra-dimensional space, superstring theory, and the holographic principle is an important component of understanding its nature. Methodology of the study is based on general research methods of analysis and synthesis, induction and deduction, mathematical and computer modeling of systems of particles and forces, use of group theory and the analogy method. Also, new theoretical models were proposed by Hawking in the aspect of treating particles near the event horizon, by Maldacena in the aspect of AdS/quantum field theory correspondence, by Witten in the aspect of the Thermal Phase Transition.
Results of considered material presents a theoretical model of a phase transition in the early stages of the evolution of the Universe, associated with a heterotic string model, identical to the phase transition of a black hole. We have shown the possibility of using symmetry groups to consider the Theory of Grand Unification. We presented nuclear theories constructed in accordance with various symmetry groups, as well as the matter content of models with extended gauge groups. String theory provides a large number of the observed features of the Universe. There are signs that string theory includes many of the qualitative features of the SM such as gauge groups and matter content [5]. These are ubiquitous features of D-brane realizations of gauge theories. Both gauge coupling unification and the matter content of the SM hint at the presence of a unified gauge group structure at high energies. Indeed, there is a natural sequence of E-group embeddings which give the SM gauge group and matter structure in an elegant manner [6-8].
Modern high energy physics is connected with experimental searches of new physics beyond the SM. Calculations of the production cross sections of rotating, non-rotating ADD microscopic BH using computer simulations and information on the searches for exotics at the LHC at 8 and 13 TeV were presented [9]. The studying of the properties of the new particles predicted by the theories of extra dimensions stimulated us to perform calculations at different parameters and energies within the RS model. Our calculations of sigma × 𝐵𝑟 of gravitons production show that the resonance peak shifts from 5 TeV to 7 TeV with increasing of energy at the colliders from 13 TeV to 14 TeV as well as the absence of peak at energy of 100 TeV at the center of mass energies [10].
In the framework of the space of extra dimensions, calculations of the energy of BH are presented and the proportionality of the energy to the number of degrees of freedom of the strings located between the branes, N, which has the meaning of the level of energy excitation of a soliton object of the D-brane type, is shown [11]. Since the entropy increases and this corresponds to an increase in the excitation level of the soliton state, the decay of BH would be accompanied by an energy release greater than the explosion of a hydrogen bomb [12].

**

References

**
1. Wigner E.P. (1970). Symmetries and Reflections: Scientific Essays. Cambridge, Mass.: M.I.T. Press, 280 p.
2. Sakita B. (1964). Supermultiplets of Elementary Particles. Phys. Rev. 136, B1756.
3. Flowers B.H., Szpikowski S. (1964). A generalized quasi-spin formalism. Proc. Phys. Soc., V. 84, 193.
4. Malyuta. Yu.M. (1969). Superfluid Quark Model. Communications of the Joint Institute for Nuclear Research, Dubna, 22 p.
5. Obikhod T.V. (2007). Spectra of superstrings. Reports of the National Academy of Sciences of Ukraine. No. 11, p. 88 - 89.
6. Beasley C., Heckman J.J., Vafa C. (2009). GUTs and exceptional branes in F-theory – I. JHEP. 0901:058. – 86 p.
7. Beasley C., Heckman J.J., Vafa C. (2009). GUTs and exceptional branes in F-theory – II. arXiv:0806.0102 [hep-th].
8. Bershadsky M., Intriligator K., Kachru S., Morrison D.R., Sadov V., Vafa C. (1996). Geometric Singularities and Enhanced Gauge Symmetries. Nucl. Phys. B481, p. 215-252.
9. Obikhod T., Petrenko I. (2016). Properties of black holes and their searches at the LHC. IOSR Journal of Applied Physics. V. 8 (Issue 6) Ver. IV. - p. 62 - 71.
10. Obikhod T., Petrenko I. (2018). Searches for Massive Graviton Resonances at the LHC. Advances in High Energy Physics. V. 2018, Article ID 3471023, 9 pages.
11. Maldacena J. (1997). Black holes and D-branes. arXiv:hep-th/9705078v1.
12. Witten E. (1998). Anti-de Sitter Space, Thermal Phase Transition, And Confinement In Gauge Theories. Adv. Theor. Math. Phys. 2, p. 505-532.

Speaker: Tetiana Obikhod (Institute for Nuclear Research NAS of Ukraine)

Obikhod.mp4

2:15 PM Determination of the electric dipole moment of heavy $\Lambda$ and $\Lambda_c^+$ baryons in electron-positron annihilation

The Universe is dominated by matter over antimatter. To theoretically explain this effect, a strong violation of CP symmetry is necessary. The currently available sources of CP symmetry breaking are not sufficient for this purpose. Therefore, the search for new sources of breaking this symmetry is a very important area of research today. One such possible source could be the electric dipole moment (EDM) of heavy baryons. In this paper, we discuss a method for determining the baryon EDM from the angular distribution of final particles in electron-positron pair annihilation processes. The question is raised with what accuracy modern experiments can determine the electric dipole moment $\Lambda$ and $\Lambda_c^+$ baryons.
Using the Monte Carlo method, pseudo-statistics of the above events were generated with a volume corresponding to the current BESIII experiment (China) and the future STCF (Super Tau-Charm Facility, China). Then, using the obtained pseudo-data, the error of measurement of the distribution parameters of these events is calculated. From these errors, the sensitivity of the measurement of the electric dipole moment of heavy $\Lambda$ and $\Lambda_c^+$ baryons are directly calculated.
For the $\Lambda$ baryon in the BESIII experiment, the calculated sensitivity for the electric dipole moment was $10^{-18}$ $e\cdot cm$, the same figure for the STCF experiment was of the order of $10^{-20}$ $e\cdot cm$. For the $\Lambda_c^+$ baryon, the calculated sensitivity for the EDM in the STCF experiment was $10^{-16}$ $e\cdot cm$.

Speaker: Mr Roman Ovsiannikov (V. N. Karazin Kharkiv National University, NSC «Kharkov Institute of Physics and Technology»)

conference.pdf

conference.pptx

Ovsiannikov.mp4

2:30 PM Energy correlation of bottom quarks from decays of top quarks in electron-positron annihilation at high energy

The purpose of the work is to study polarization effects in the presence of CP violation in the process of $e^+e^-$ annihilation with a focus on the future electron-positron collider CLIC with energy $\sqrt{s} = 380$ GeV. The study is primarily focused on the annihilation of electron-positron pairs into top quark pairs, which, upon decay, produce bottom quarks and W bosons. The Lagrangian describing the interaction of quarks with carrier particles such as photons and Z bosons was modified to account for CP-violation effects by including terms proportional to the electric and weak dipole moments.

As a result, the cross-section of the process was obtained as a function of several important variables, such as the energies of bottom quarks and electrons, the polarizations of the initial electron beams, scalar and pseudo-scalar interaction constants of the Higgs boson with top quarks, which determine the appearance of CP disturbance effects. The asymmetry in the number of events in which the energies of bottom quarks are measured in experiments compared to the energies of anti-bottom quarks was analyzed. The physical aim is to detect differences between the number of events in which the energy of the bottom quark is greater than the energy of the antiquark, and the number of events in the opposite case. The study also took into account the observed difference in average energies between bottom quarks and antiquarks when exposed to varying degrees of polarization in the initial electron beam. These observables are sensitive to the CP-violation.

Speaker: Ivan Truten (NSC Kharkiv Institute of Physics and Technology, Kharkiv, Ukraine)

Talk_Truten_CERN-Ukraine.pdf

Truten.mp4

2:45 PM Four types of phase transitions in interacting meson (boson) matter at high temperatures

Within the framework of the mean field model, the thermodynamics of the relativistic scalar system of interacting particles and antiparticles in the presence of a Bose-Einstein condensate was investigated. It is assumed that the total isospin (charge) density is conserved. It is shown that the particle-antiparticle boson system reveals four types of phase transitions into the condensate phase. Three types belong to the phase transition of the second order and one to the first order. We show that the grand canonical ensemble is not suitable for describing bosonic system of particles and antiparticles in the presence of a condensate, but an adequate study can be carried out within the framework of the canonical ensemble, where the chemical potential is a thermodynamic quantity that depends on the canonical free variables.

Speakers: Dr Denys Zhuravel (Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine), Prof. Dmitry Anchishkin (Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine)

Talk-CERN_Zhuravel.pdf

Zhuravel.mp4

3:00 PM Critical Point and Onset of Deconfinement

The talk briefly presents history, status, and plans of the search for the critical structures — the onset of deconfinement and the QCD critical point — in high-energy nucleus–nucleus collisions. The basic ideas are introduced, and the path towards the quark–gluon plasma discovery is sketched. Then the status of the search for the deconfinement critical point is discussed.

Speaker: Mark Gorenstein (BITP Kyiv)

gorenstein-2024-2 .pdf

gorenstein-2024-2 .ppt

Gorenstein.mp4

3:15 PM Axial Channeling and Stochastic Deflection as Tools to Manipulate Trajectories of Charged Particle Beams

When a charged particle beam closely aligns with the atomic axis of a crystal, the particles are confined within this axis. The crystal's bending, a result of this alignment, steers the beam's trajectory. Early attempts to observe this phenomenon experimentally were unsuccessful, but subsequent trials at CERN, based on the predictions of Grinenko and Shul'ga, have confirmed the effectiveness of axial channeling and stochastic deflection for beam steering. Initial tests were carried out with 400 GeV proton beams, and the technique has since been expanded to include negatively charged particle beams. This conference contribution will highlight the significant achievements in manipulating high-energy particle beams through axial channeling in bent crystals.

Speaker: Dr Andrea Mazzolari (INFN)

Mazzolari.mp4

3:30 PM Correlation between multiple scattering angle and ionization energy loss in electron detectors

There is a significant correlation between the angle of multiple scattering and the ionization energy loss for relativistic electrons in an amorphous medium, which can be used in high-energy electron and positron detectors [1]. The correlation is found to be the most pronounced at deflection angles larger than typical, reflecting the underlying single-scattering kinematical correlation, but is also sizable at typical deflection angles, where the width of the angular distribution increases with the increase of the energy loss.
Experimental verification of the predicted correlation should be feasible with silicon targets, by observing 10% differences between angular distributions measured at different values of the ionization energy loss. Stronger (∼20%) correlation effects may be measurable with the aid of organic semiconductors.
[1] M. V. Bondarenco, Phys. Rev. D 103, 096026 (2021).

Speaker: Micola Bondarenco

Bondarenco.mp4

3:45 PM Modeling soft physics in heavy ion collision experiments: from GeV to TeV energies

The goal of the presented study is investigation of the properties and evolution dynamics of new forms of matter created in nucleus-nucleus (and nucleon – nucleon with large multiplicity) collisions at high energies varying in the widest relativistic range, from a few GeV up to ten TeV per nucleon pair, within a unified model, describing in detail the full process of matter evolution, including its possible thermalization at the initial phase of collision. The problem of the phase transition between quark-gluon and hadron states of matter, as well as possible existence of the corresponding critical end point is one of the most interesting in this regard. The research will include extending the existing realistic collision model, iHKM (integrated HydroKinetic Model), proven to be successful in description/prediction of the all soft physics results for ultra-high energy collisions, to make it also cover the region of low and intermediate relativistic energies.

Speaker: Yuriy Sinyukov (Bogolyubov Institute for Theoretical Physics)

Sinyukov.mp4

4:00 PM Dip-bump structure in proton diffractive dissociation at the LHC

For the first time a dip and bump in the differential cross section of
proton diffractive dissociation at t=-4 (GeV)^2 and various missing
masses, typical of present and future LHC measurements is predicted.
Future experiments at the LHC will verify the prediction and the model
behind it.

Speakers: Prof. Laszlo Jenkovszky (Bogolubov ITP, Kiev), Laszlo Jenkovszky (National Academy of Sciences of Ukraine), László Jenkovszky (BITP)

Cern_Ukr 2.pdf

Cern_Ukr 2.pptx

Jenkovsky.mp4

4:15 PM → 5:00 PM Conference Closing & Outlook

Convener: Boris Grynyov (National Academy of Sciences of Ukraine (UA))

BG-ESPP.pdf

European Strategy 2020

RO_Input_ESPP_2020.pdf