What We Do – HEP Group VINČA

Higgs Physics

Related to the only discovery at LHC, Higgs studies are in the focus of future HEP projects

6 completed analyses
CLICdp Collaboration, Higgs physics at the CLIC electron-positron linear collider, Eur.Phys.J. C77 (2017) 7.475, IF 4.1

Higgs to EW: g_HZZ at 350 GeV, 1.4 TeV and 3 TeV CLIC
N.Vukasinovic, I. Bozovic et al. (8 authors), Measurement of the H to ZZ branching fraction at a 350 GeV and 3 TeV CLIC, Phys.Rev. D Vol. 105. 092008 (2022), IF 5.0
Higgs rare decays: g_Hμμ at 1.4 TeV CLIC
G. Milutinovic-Dumbelovic, I. Bozovic-Jelisavcic et al. (8 authors), Physics potential for the measurement of σ(Hν̅ν) x BR(H→μ+μ-) at the 1.4 TeV CLIC collider, Eur.Phys.J. C75 (2015) 11, 515, IF 4.1
Higgs rare decays: g_Hγγ at 3 TeV CLIC
G.Kacarevic, I. Bozovic et al. (8 authors), Measurement of the Higgs boson branching ratio BR(H→γγ) at a 3 TeV CLIC, Phys. ReV. D 105. 092009 (2022), IF 5.0
CP violation in HZZ vertex in VBF at 1 TeV ILC
N.Vukasinovic, I. Bozovic, et al. (4 authors), Probing CPV mixing in the Higgs sector in VBF at 1 TeV ILC, Phys. ReV. D 110. 032011 (2024), IF 5.0

HIGGS PHYSICS

Higgs factories are top-priority of the European Strategy for Particle Physics and it is plausible to stay that way in the 2025 Update. HEP group Vinča is involved in several Higgs factory projects: CLIC, CEPC and ILC, addressing measurements of the Higgs couplings, and the most recently, capabilities of these machines to measure Higgs CP structure. In this respect, we have delivered the first estimate of statistical precision to measure CP violation in HZZ vertex in VBF (ZZ-fusion). A PhD thesis is ongoing on CPV in Higgs to tau-tau decays at CEPC.

SOME MORE RESULTS

(4) is the first CPV estimate in VBF at an e+e- collider

(1) and (4) are input to the ECFA Higgs/to/EW Group for the EPPSU 2025

PhD theses:

CERN-THESIS-2017-349
CERN-THESIS-2023-343
CERN-THESIS-2024-249

Detector R&D

CEPC

CEPC CDR study on precision of ℒ_intCEPC Conceptual Design Report: Volume 2 – Physics & Detector, CEPC Study Group, (Machine detector interface and luminosity detectors, I. Bozovic Jelisavcic, S. Hou and H. Zhu (ed.)), Nov 23, 2018. 424 pp., IHEP-CEPC-DR-2018-02, IHEP-EP-2018-01, IHEP-TH-2018-01, e-Print: arXiv:1811.10545[hep-ex]
Systematics in ℒ_intmeasurement
Ivan Smiljanic, Ivanka Bozovic Jelisavcic, et al. (6 authors), Systematic uncertainties in integrated luminosity measurement at CEPC, JINST 17 P09014. (2022)
Metrology for the ℒ_int measurement at the Z-pole
Ivan Smiljanic, Ivanka Bozovic Jelisavcic, et al (5 authors), Uncertainties from metrology in the integrated luminosity measurement with the updated design of a detector at CEPC, Progress of Theoretical and Experimental Physics, ptae141 (2024), IF 8.6

Instrumentation of the very farward region at ILC/ILD
I. Bozovic Jelisavcic et al. (5 authors), Luminosity measurement at ILC, JINST 8 (2013) P08012
Systematics in ℒint measurement ILC & CLIC
S. Lukic, I. Bozovic Jelisavcic, et al. (4 authors), Correction of beam-beam effects in luminosity measurement in the forward region at CLIC, JINST 8 (2013) P05008
Metrology for the ℒ_int measurement at all ILC energies
I.Smiljanic, I.Bozovic, G.Kacarevic, M.Radulovic, and J.Stevanovic, Metrology requirements for the integrated luminosity measurement using small-angle Bhabha scattering at ILC, ILD-PHYS-2024-003, Progress of Theoretical and Experimental Physics, ptaf015, (2025) IF 8.6

MDI AND LUMINOSITY

Going along the lines of the European Strategy, detector R&D for future e⁺e^– colliders is pursued: 1) to define critical performance of detector sub-systems at linear and circular colliders for the Higgs measurements; 2) to realize compact calorimetry for future Higgs factories, based on already very well integrated HEP group activities in the FCAL, ILD and CEPC collaborations. Luminosity is the number of collisions that can be produced in a detector per square cm and per second. Although it can be determined from a QED Bhabha scattering by simple counting, control of the integrated luminosity relative uncertainty at the level of 10^-4 posses serious challenges for instrumentation of the MDI region of a detector at future electron-positron colliders. We are currently focused on systematic uncertainties in luminosity measurement at linear (ILC) and circular (CEPC) colliders rising from metrology of luminometer position and beam delivery. With this study we have contributed to MDI design studies summarized in Chapter 9 of the CEPC-CDR, while (3) and (6) are the input of the ECFA Precision Group for the ESPPU 2025.