Publications

Order by: publication date number of citations

• Apparent fine tunings for field theories with broken space-time symmetries

  Alberto Nicolis, Ira Z. Rothstein

  SciPost Phys. 16, 045 (2024) · published 9 February 2024 | Toggle abstract · pdf

  We exhibit a class of effective field theories that have hierarchically small Wilson coefficients for operators that are not protected by symmetries but are not finely tuned. These theories possess bounded target spaces and vacua that break space-time symmetries. We give a physical interpretation of these theories as generalized solids with open boundary conditions. We show that these theories realize unusual RG flows where higher dimensional (seemingly irrelevant) operators become relevant even at weak coupling. Finally, we present an example of a field theory whose vacuum energy relaxes to a hierarchically small value compared to the UV cut-off.

• The scattering and neutrino detector at the LHC

  Giovanni De Lellis

  SciPost Phys. Proc. 12, 051 (2023) · published 5 July 2023 | Toggle abstract · pdf

  SND@LHC, Scattering and Neutrino Detector at the LHC, is a compact experiment designed to perform measurements with neutrinos produced at the LHC in the unexplored pseudo-rapidity region of 7.2 < $\eta$ < 8.4, complementary to all the other experiments at the LHC. The experiment was approved in March 2021. It was constructed in about one year and it is now taking data during the Run 3 of the LHC. In this paper we review the detector concept, the physics case and the status of the data taking.

• Asymmetric Bethe Ansatz

  Steven G. Jackson, Hélène Perrin, Gregory E. Astrakharchik, Maxim Olshanii

  SciPost Phys. Core 7, 062 (2024) · published 12 September 2024 | Toggle abstract · pdf

  The recently proposed exact quantum solution for two $\delta$-function-interacting particles with a mass-ratio $3\!:\!1$ in a hard-wall box [Y. Liu, F. Qi, Y. Zhang and S. Chen, iScience 22, 181 (2019)] violates the conventional necessary condition for a Bethe Ansatz integrability, the condition being that the system must be reducible to a superposition of semi-transparent mirrors that is invariant under all the reflections it generates. In this article, we found a way to relax this condition: some of the semi-transparent mirrors of a known self-invariant mirror superposition can be replaced by the perfectly reflecting ones, thus breaking the self-invariance. The proposed name for the method is asymmetric Bethe Ansatz (asymmetric BA). As a worked example, we study in detail the bound states of the nominally non-integrable system comprised of a bosonic dimer in a $\delta$-well. Finally, we show that the exact solution of the Liu-Qi-Zhang-Chen problem is a particular instance of the the asymmetric BA.

• Development of the ATLAS Liquid Argon Calorimeter Readout Electronics for the HL-LHC

  Mathis Kolb

  SciPost Phys. Proc. 8, 158 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The full ATLAS Liquid Argon Calorimeter electronic readout chain will be upgraded for the high-luminosity LHC. The upgrade is designed to withstand the expected radiation level and to be compatible with the Phase-I Digital Trigger System which is being installed right now. Analogue electronics shape and amplify the calorimeter signals before they are digitized with 16 bit dynamic range on two gain scales. The on-detector system samples the calorimeter cell signals at 40 MHz and sends them to the off-detector electronics which apply digital processing based on FPGAs. Design studies and tests of prototypes of the upgraded components are present

• Exclusive electro-weak production of a charmed meson at high energy

  B. Pire, L. Szymanowski, J. Wagner

  SciPost Phys. Proc. 8, 150 (2022) · published 14 July 2022 | Toggle abstract · pdf

  Exclusive electro-weak processes have peculiar features which make them complementary to usually discussed deeply virtual electroproduction processes such as deep virtual Compton scattering or meson production (and the corresponding crossed reactions). They allow in particular single charmed meson production, which we study in two different contexts : electroproduction at an electron ion collider and neutrino-production at a medium energy neutrino facility. We rely on the QCD collinear factorization framework where generalized parton distributions allow physicists to perform a nucleon tomography.

• Eikonal Dressed Gluon Exponentiation to study power corrections to Thrust, C-parameter, and Angularity

  Neelima Agarwal, Ayan Mukhopadhyay, Sourav Pal, Anurag Tripathi

  SciPost Phys. Proc. 7, 020 (2022) · published 21 June 2022 | Toggle abstract · pdf

  Dressed Gluon Exponentiation is a well known method to study power corrections. We present here its eikonalized version -- Eikonal Dressed Gluon Exponentiation (EDGE) \cite{Agarwal:2020uxi} to determine the dominant power corrections to shape variables such as Thrust, $ C $- parameter, and Angularity. Our method remarkably simplifies the calculations.

• RG flows in de Sitter: C-functions and sum rules

  Manuel Loparco

  SciPost Phys. 17, 079 (2024) · published 12 September 2024 | Toggle abstract · pdf

  We study the renormalization group flow of unitary Quantum Field Theories on two-dimensional de Sitter (dS) spacetime. We prove the existence of two functions of the radius of dS that interpolate between the central charges of the UV and IR fixed points of the flow when tuning the radius $R$ while keeping the mass scales fixed. The first is constructed from certain components of the two-point function of the stress tensor evaluated at antipodal separation. The second is the spectral weight of the stress tensor in the $\Delta=2$ discrete series. This last fact implies that the stress tensor of any unitary QFT in dS$_2$ must interpolate between the vacuum and states in the $\Delta=2$ discrete series irrep. We verify that the c-functions are monotonic for intermediate radii in the free massive boson and free massive fermion theories, but we lack a general proof of said monotonicity. We derive a variety of sum rules that relate the central charges and the c-functions to integrals of the two-point function of the trace of the stress tensor and to integrals of its spectral densities. The positivity of these formulas implies $c^{UV}≥ c^{IR}$. In the infinite radius limit the sum rules reduce to the well known formulas in flat space. Throughout the paper, we prove some general properties of the spectral decomposition of the stress tensor in dS$_{d+1}$.

• Constant-time quantum algorithm for homology detection in closed curves

  Nhat A. Nghiem Vu, Xianfeng David Gu, Tzu-Chieh Wei

  SciPost Phys. 15, 049 (2023) · published 4 August 2023 | Toggle abstract · pdf

  Given a loop or more generally 1-cycle $r$ of size L on a closed two-dimensional manifold or surface, represented by a triangulated mesh, a question in computational topology asks whether or not it is homologous to zero. We frame and tackle this problem in the quantum setting. Given an oracle that one can use to query the inclusion of edges on a closed curve, we design a quantum algorithm for such a homology detection with a constant running time, with respect to the size or the number of edges on the loop $r$, requiring only a single usage of oracle. In contrast, classical algorithm requires $\Omega(L)$ oracle usage, followed by a linear time processing and can be improved to logarithmic by using a parallel algorithm. Our quantum algorithm can be extended to check whether two closed loops belong to the same homology class. Furthermore, it can be applied to a specific problem in the homotopy detection, namely, checking whether two curves are not homotopically equivalent on a closed two-dimensional manifold.

• Few-nucleon system dynamics studied via deuteron-deuteron collisions at 160 MeV

  I. Ciepał , K. Bodek, N. Kalantar-Nayestanaki , G. Khatri , St. Kistryn , B. Kłos, A. Kozela , J. Kuboś, P. Kulessa , A. Łobejko, A. Magiera , J. Messchendorp , I. Mazumdar, W. Parol , R. Ramazani-Sharifabadi, D. Rozpędzik , I. Skwira-Chalot , E. Stephan, A. Wilczek , B. Włoch, A. Wrońska , J. Zejma

  SciPost Phys. Proc. 3, 018 (2020) · published 25 February 2020 | Toggle abstract · pdf

  Four nucleon scattering at intermediate energies provides unique opportunities to study effects of the two key ingredients of the nuclear dynamics, the nucleon-nucleon P-wave (NNP-wave) and the three-nucleon force (3NF). This is possible only with systematic and precise data, in conjunction with exact theoretical calculations. Using the BINA detector at KVI Groningen, the Netherlands, a rich set of differential cross section of the 2H(d, dp)n breakup reaction at 160 MeV deuteron beam energy has been measured. Besides the three-body breakup, also cross sections of the 2H(d, 3He)n proton transfer reaction have been obtained. The data are compared to the recent calculations for the three-cluster breakup.

• Constraining the nuclear gluon PDF with inclusive hadron production data

  P. Duwentäster, L. A. Husová, T. Ježo, M. Klasen, K. Kovařík, A. Kusina, K. F. Muzakka, F. I. Olness, I. Schienbein, J.Y. Yu

  SciPost Phys. Proc. 8, 045 (2022) · published 12 July 2022 | Toggle abstract · pdf

  The nuclear parton distribution functions (nPDFs) of gluons are known to be difficult to determine with fits of deep inelastic scattering (DIS) and Drell-Yan (DY) data alone. Therefore, the nCTEQ15 analysis of nuclear PDFs added inclusive neutral pion production data from RHIC to help in constraining the gluon. In this analysis, we present a new global analysis of nuclear PDFs based on a much larger set of single inclusive light hadron data from RHIC and the LHC. Using our new nCTEQ code (nCTEQ++) with an optimized version of INCNLO we study systematically the limitations of the theory and the impact of the fragmentation function uncertainty.