Vol. 3 No. 2 (2022): Suplemento de la Revista Mexicana de Física. Joint Proceedings of the XXXV Annual Meeting of the DPyC-SMF & XIX Mexican School on Particles and Fields

07 Joint Proc. XXXV Annual Meeting DPyC-SMF & XIX Mexican School on Particles an

• Preface

  Organizing Committee

  i-vii

  Abstract:

  Preface

  XXXV Annual Meeting of the DPyC-SMF, May 11-13, 2021
  XIX Mexican School on Particles and Fields, August 9-13, 2021

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• Homenaje a Salvador Carrillo Moreno (1965 - 2021)

  Cecilia Uribe Estrada

  020701 1-3

  Abstract:

  Salvador was born on the 10th of March, 1965 in Mexico City and grew up in Guanajuato. He received his bachelor’s degree in physical engineering in 1990 from the Ibero-American University in Mexico City. It was during this period that he met his future life partner and wife, our friend and colleague Fabiola Vázquez. He obtained his Master’s degree in sciences (physics) from the Center for Research and Advanced Studies (CINVESTAV) of the National Polytechnic Institute (IPN) in 1995, where he also obtained his doctorate in sciences (physics) in March, 2003. From 2000 until his departure he worked full-time as an academic at the Ibero-American University in Mexico City. Salvador left an indelible mark on the particle physics community both domestically as well as internationally. His work in research, education, science outreach and his dedication in supporting the indigenous communities of our country has left an important legacy which will continue to bear fruit.

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• Tribute to Arnulfo Zepeda Domínguez

  J. C. Arteaga-Velazquez, Karen Salome Caballero Mora, R. López Ramírez, H. Martínez Huerta, R. Pelayo-Ramos, L. Villaseñor

  020702 1-9

  Abstract:

  On November 30, 2020, the world of High Energy Physics lost one of its most brilliant research professors. Dr. Arnulfo Zepeda Dom ́ınguez left a great legacy of scientific results, new researchers’ training, schools’ creation, new experiments, new research centers, and invaluable scientific outreach work. In this contribution, a group of his students, colleagues, and friends describe him as a professor and leader through several anecdotes.

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• Geometry and causal flux in multi-loop Feynman diagrams

  German Fabricio Roberto Sborlini

  020703 1–7

  Abstract:

  In this review, we discuss recent developments concerning efficient calculations of multi-loop multi-leg scattering amplitudes. Inspired by the remarkable properties of the Loop-Tree Duality (LTD), we explain how to reconstruct an integrand level representation of scattering amplitudes which only contains physical singularities. These so-called causal representations can be derived from connected binary partitions of Feynman diagrams, properly entangled according to specific rules. We will focus on the detection of flux orientations which are compatible with causality, describing the implementation of a quantum algorithm to identify such configurations.

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• New limits from lepton flavour violating processes on the Littlest Higgs model with T-parity

  Iván Pacheco, Pablo Roig

  020704 1-10

  Abstract:

  We study lepton flavor violation (LFV) within the Littlest Higgs Model with T parity (LHT) realizing an inverse seesaw (ISS) mechanism of type I. In this scenario there appear new $\mathcal{O}$(TeV) Majorana neutrinos, driving LFV. We are analyzing the heavy Majorana neutrinos effects on LFV processes: $\ell \to \ell' \gamma$, $Z \to \bar{\ell}\ell'$, $L \to 3 \ell$ decays and $\mu \to e$ conversion in nuclei but we emphasize Type III decay channel of $L \to 3 \ell$ which are known as "wrong-sign": $\ell \rightarrow \ell' \ell'' \Bar{\ell}'''$ satisfying $\ell \neq \ell' = \ell'' \neq \ell'''$, since these processes vanish in the traditional LHT. First, we get values to $| \theta_{ej} \theta^{\dagger}_{\mu j}|$, $| \theta_{ej} \theta^{\dagger}_{\tau j}|$, and $| \theta_{\mu j} \theta^{\dagger}_{\tau j}|$ through $\ell \to \ell' \gamma$. With aid of these limits for mixing matrices, we can demonstrate that results for branching ratios of wrong sign processes yield within one order of magnitude below present bounds. We do not expect large correlations among the two wrong-sign decay modes. Also, we see that the mean values of heavy Majorana neutrino masses for all LFV processes are quasi-degenerate around 4 TeV.

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• Ramanujan summation and the Casimir effect

  Wolfgang Bietenholz

  020705 1-6

  Abstract:

  Srinivasa Ramanujan was a great self-taught Indian mathematician, who died a century ago, at the age of only 32, one year after returning from England. Among his numerous achievements is the assignment of sensible, finite values to divergent series, which correspond to Riemann's $\zeta$-function with negative integer arguments. He hardly left any explanation about it, but following the few hints that he gave, we construct a direct justification for the best known example, based on analytic continuation. As a physical application of Ramanujan summation we discuss the Casimir effect, where this way of removing a divergent term corresponds to the renormalization of the vacuum energy density, in particular of the photon field. This leads to the prediction of the Casimir force between conducting plates, which has now been accurately confirmed by experiments. Finally we review the discussion about the meaning and interpretation of the Casimir effect. This takes us to the mystery surrounding the magnitude of Dark Energy.

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• The anomalous magnetic moment of the muon: short overview

  Pablo Roig Garcés

  020706 1-9

  Abstract:

  We critically review the current status of the muon g−2, where the Standard Model prediction deviates at 4.2σ from the experimental average, which is tantalizing for new physics interpretations.

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• New insight in the 2-flavor Schwinger model based on lattice simulations

  Jaime Fabián Nieto Castellanos, Wolfgang Bietenholz, Ivan Hip

  020707 1-5

  Abstract:

  We consider the Schwinger model with two degenerate, light fermion flavors by means of lattice simulations. At finite temperature, we probe the viability of a bosonization method by Hosotani {\it et al.} Next we explore an analogue to the pion decay constant, which agrees for independent formulations based on the Gell-Mann--Oakes--Renner relation, the 2-dimensional Witten--Veneziano formula and the $\delta$-regime. Finally we confront several conjectures about the chiral condensate with lattice results.

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• The odderon discovery by the D0 and TOTEM collaborations

  Christophe Royon

  020708 1-6

  Abstract:

  We describe the discovery of the colorless $C$-odd gluonic compound, the odderon, by the D0 and TOTEM Collaborations by comparing elastic differential cross sections measured in $pp$ and $p \bar{p}$ interactions at high energies.

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• Dyson-Schwinger equations and the muon g-2

  Khépani Raya, Adnan Bashir, Ángel S. Miramontes, Pablo Roig

  020709 1-9

  Abstract:

  We present a brief introduction to the Dyson-Schwinger equations (DSEs) approach to hadron and high-energy physics. In particular, how this formalism is applied to calculate the electromagnetic form factors $\gamma^* \gamma^* \to \textbf{P}^0$ and $\gamma^* \textbf{P}^\pm \to \textbf{P}^\pm$ (with $\textbf{P}^\pm$ and $\textbf{P}^0$ charged and neutral ground-state pseudoscalar mesons, respectively) is discussed. Subsequently, the corresponding contributions of those form factors to the muon anomalous magnetic moment ($g-2$) are estimated. We look forward to promoting the DSE approach to address theoretical aspects of the muon $g-2$, highlighting some calculations that could be carried out in the future.

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• One loop mechanism for neutrinoless double beta hyperon decay

  Gerardo Hernández Tomé

  020710 1-8

  Abstract:

  Motivated by the large dataset to be accumulated of hyperon pairs produced in decays of $\mathcal{O}(10^{10})$ $J/\psi$ and $\psi^\prime$ charmonia states in the BES-III collaboration, we revisited the predictions of $\Delta L=2$ decays of hyperons $B^-_i\to B^+_f\ell^-\ell'^-$ in the one-loop model mechanism involving Majorana neutrinos previously presented in \cite{Barbero:2002wm}. Unlike the previous work, by modeling the momentum transfer dependence of the hyperon form factors in the computation we provide finite results for the loop integration. Furthermore, since we keep finite masses for the neutrinos throughout the calculations, we are able to consider the effects of heavy Majorana neutrinos. Thus, our results are applied to a simple model that involves two Majorana heavy neutrinos in the framework of a low-scale seesaw model. In order to provide and compare additional predictions, we study an alternative model where $\Delta L=2$ decays are induced by the short-range effects of a scalar boson coupled to di-leptons.

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• ν-e Scattering radiative corrections in a short baseline experiment

  O. G. Miranda, Guadalupe Moreno Granados, C. A. Moura

  020711 1-6

  Abstract:

  Precision tests in future long-baseline experiments will measure neutrino oscillation properties with high accuracy. Besides, with their near detectors will be possible to perform measurements with high statistics, such as neutrino scattering with electrons, among other neutrino interactions. Near detectors will give the chance to measure the radiative corrections of this process with unprecedented precision. This work will discuss how the test of the radiative corrections in the neutrino-electron scattering may measure the neutrino charge radius.

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• Parton distribution effects in the direct photon production at hadron collisions

  David Francisco Rentería Estrada, Roger Hernández-Pinto, German Sborlini

  020712 1-5

  Abstract:

  Parton distribution functions are crucial to understand the internal kinematics of hadrons. There are currently a large number of distribution functions on the market, and thanks to today's technology, performing computational analysis of the differential cross-sections has become more accessible. Despite technological advances, accurately accessing to the internal structure of hadrons remains a difficult task from a theoretical point of view. In this work, we analyze the impact on the differential cross-sections when updating the sets of parton distribution and fragmentation functions, for the production of one hadron plus a direct photon at the energy scale of RHIC and LHC experiments.

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• The structure of cosmic strings of a U(1) gauge field for the conservation of B - L

  Victor Muñoz-Vitelly, José Antonio García-Hernández, Wolfgang Bietenholz

  020713 1-7

  Abstract:

  We consider an extension of the Standard Model, where the difference between the baryon number $B$ and the lepton number $L$ is gauged with an Abelian gauge field, in order to explain the exact conservation of $B-L$. To avoid a gauge anomaly, we add a right-handed neutrino $\nu_{\rm R}$ to each fermion generation. Here it is not sterile, so the usual Majorana term is excluded by gauge invariance. We provide a mass term for $\nu_{\rm R}$ by adding a non-standard 1-component Higgs field, thus arriving at a consistent extension of the Standard Model, where the conservation of $B-L$ is natural, with a modest number of additional fields. We study the possible formation of cosmic strings by solving the coupled field equations of the two Higgs fields and the non-standard U(1) gauge field. Numerical methods provide the corresponding
  string profiles, depending on the Higgs winding numbers, such that the appropriate boundary conditions in the string center and far from it are fulfilled.

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• A short review of the Casimir effect with emphasis on dynamical boundary conditions

  Benito Alberto Juárez Aubry, Ricardo Weder

  020714 1-7

  Abstract:

  We give a short review on the static and dynamical Casimir effects, recalling their historical prediction, as well as their more recent experimental verifications. We emphasise on the central role played by so-called dynamical boundary conditions (for which the boundary condition depends on a second time derivative of the field) in the experimental verification of the dynamical Casimir effect by Wilson et al. We then go on to review our previous work on the static Casimir effect with dynamical boundary conditions, providing an overview on how to compute the so-called local Casimir energy, the total Casimir energy and the Casimir force. We give as a future perspective the direction in which this work should be generalised to put the theoretical predictions of the dynamical Casimir effect experiments on a rigorous footing.

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• Physics of the tau lepton

  Jorge Portoles

  020715 1-11

  Abstract:

  Within our present knowledge, the tau is the heaviest lepton and the only one decaying into hadrons, a fact that makes it the source of a very rich phenomenology. It represents the third family of leptons in the Standard Model, a feature that helps its classification but whose real meaning is not asserted yet. The tau lepton provides: i) a clean and unique environment to study both the hadronization of QCD currents, in an energy region populated by resonances, and the phenomenological determination of relevant parameters of the Model; ii) together with the muon, they have a very constrained flavour dynamics (in the absence of neutrino masses) due to an accidental global symmetry of the Standard Model. In consequence, the tau lepton brings an excellent benchmark for the study of QCD at low energies and, at the same time, for the search of new physics.

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• Detector control system for forward diffractive detector

  Juan Manuel Mejia Camacho, Juan Carlos Cabanillas Noris, I. León-Monzón

  020716 1-4

  Abstract:

  The proposal of this work is an update on the development of a control system (DCS, Detector Control System) for the new FDD detector and its integration in the ALICE experiment, according to the rules of the new Online-Offline (O2) infrastructure for Run 3 of the LHC, by using the SCADA system (Supervisory Control and Data Acquisition) called WinCC-OA . This proposal will allow the DCS of FDD detector to have an optimal performance in the physical data acquisition runs, mainly.

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• The first measurement of the muon anomalous magnetic moment from the Fermilab Muon g−2 collaboration

  Booth Tewsley-Booth

  020717 1-6

  Abstract:

  This paper will cover the physics and methods behind Fermilab’s Muon g-2 Experiment, along with the long-awaited results from Run-1. The experiment was undertaken to resolve the tension between the Standard Model and the previous measurement taken at Brookhaven National Laboratory. The measured value of the muon magnetic anomaly is a_µ(FNAL) = 116592040(54) × 10⁻¹¹. This result is in good agreement with Brookhaven’s previous measurement. The new world average, a_µ(Exp) = 116592061(41) × 10⁻¹¹, shows a difference from the theoretical value of the Standard Model (SM), a_µ(SM) = 116591810(43) × 10⁻¹¹, of 4.2 standard deviations, strongly hinting at physics beyond the Standard Model. The experiment requires the simultaneous measurement of the muon precession frequency, the magnetic field, and the muons’ distribution in the field. All three of these measurements will be discussed in context, along with the main systematic corrections and uncertainties.

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• Global analysis of NSI in exclusive semileptonic tau decays

  Javier Rendón

  020718 1-7

  Abstract:

  We perform a global analysis of exclusive hadronic tau decays into one and two mesons using the low-energy limit of the Standard Model Effective Field Theory up to dimension six, assuming left-handed neutrinos. A controlled theoretical input on the Standard Model hadronic form factors, based on chiral symmetry, dispersion relations, data and asymptotic QCD properties, has allowed us to set bounds on the New Physics (NP) effective couplings using the present experimental data. Our results highlight the importance of semileptonic τ decays in complementing the traditional low-energy probes, such nuclear β decays or semileptonic pion and kaon decays, and the high-energy measurements at LHC scales. This makes yet another reason for considering hadronic tau decays as golden modes at Belle-II.

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• Axial-vector contributions to the HFS of muonic hydrogen

  Jesús Alejandro Miranda Hernández, Pablo Roig Garcés, Pablo Sánchez Puertas

  020719 1-6

  Abstract:

  We review the axial-vector meson contributions to the HFS of muonic hydrogen. We evaluate the impact of the singly- and doubly-virtual asymptotic behavior of the transition form factors of the axial-vector mesons. As our main result, we find an opposite sign (and a factor of 2 difference) concerning previous analyses and a novel discussion of the hadronic modeling.

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• Four-loop scattering amplitudes through the loop-tree duality

  Norma Selomit Ramírez Uribe

  020720 1-6

  Abstract:

  A general outlook is presented on the study of multiloop topologies appearing for the first time at four loops. A unified description and representation of this family is provided, the so-called N⁴MLT universal topology. Based on the Loop-Tree Duality framework, we discuss the dual opening of this family and expose the relevance of a causal representation. We explore an alternative procedure for the search of causal singular configurations of selected N⁴MLT Feynman diagrams through the application of a modified Grover's quantum algorithm.

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• The electroweak standard model

  Jose Ignacio Illana

  020721 1-30

  Abstract:

  After introducing the basic symmetry principles, the full Lagrangian is derived in detail and the most relevant aspects of the electroweak phenomenology are discussed with special emphasis on the determination of the input parameters and the consistency checks of the model.

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• Design of the TEPX luminometer for the CMS experiment at the HL-LHC

  Jose Feliciano Benitez, Hedwin Aaron Encinas Acosta, Ashish Sehrawat, Cristina Oropeza Barrera

  020722 1-4

  Abstract:

  The design and expected performance for precision luminosity measurement of the Tracker Endcap Pixel (TEPX) detector for the CMS experiment at the upcoming High-Luminosity LHC (HL-LHC) is described. The TEPX detector is composed of 4 double-sided double disks at each end of CMS covering the range of | z | from 175 to 265 cm, each disk made of 5 rings composed of silicon sensors, with a total of 800 million pixels distributed across the 8 disks. Disk 4 Ring 1 (TEPXD4R1) will be dedicated to luminosity and beam-induced background measurements, utilising the same method as that of the rest of TEPX, namely pixel cluster counting. For the HL-LHC, the goal is to achieve a final uncertainty of 1% for offline luminosity measurements. The expected performance of the TEPX and TEPXD4R1 luminometers in terms of statistical precision for van der Meer scan calibration and for physics conditions, as well as the linearity performance of each disk are presented.

   

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• Phenomenological studies in the 2HDM and SM using Madgraph 5

  Sergio Sicairos-Paez, Roger Hernández Pinto

  020723 1-5

  Abstract:

  The phenomenological analysis of an extension of the Standard Model is analyzed in this manuscript. The Two Higgs Doublet Model is a simple way to incorporate a second extra doublet to the Standard Model to reduce the tension between experimental measurements and theoretical predictions. This model presents a large phenomenological signals which could guide the search for new physics at hadron colliders. In particular, we study the transverse momentum, the rapidity and the angular distributions of the jets in the $pp \to j j h$ channel within the Standard Model and the Two Higgs Doublet Model in the LHC and FCC environment by means of Monte Carlo simulations made in MadGraph 5.

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• Semi-vortices and cluster-vorticity: new concepts in the Berezinskii-Kosterlitz-Thouless phase transition

  Brandon Gómez Bravo, Bryan David Juárez Hernández, Wolfgang Bietenholz

  020724 1-6

  Abstract:

  The Berezinski˘ı-Kosterlitz-Thouless (BKT) essential phase transition in the 2d XY model is revisited. Its mechanism is usually described by the (un)binding of vortex–anti-vortex (V–AV) pairs, which does, however, not provide a clear-cut quantitative criterion for criticality. Known sharp criteria are the divergence of the correlation length and a discontinuity of the helicity modulus. Here we propose and probe a new criterion: it is based on the concepts of semi-vortices and cluster vorticity, which are formulated in the framework of the multi-cluster algorithm that we use to simulate the 2d XY model

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• Dark matter and neutrinos in Left-Right Mirror Model with Z2 symmetry

  M. A. Arroyo-Ureña, R. Gaitan, J. Lamprea, Jose Halim Montes de Oca Yemha, T. A. Valencia-Pérez

  020725 1-4

  Abstract:

  We discussed the feasibility of including dark matter in the Left-Right Mirror Model with an additional discrete Z₂ symmetry. The Z₂ symmetry helps to prevent any decay of the possible dark matter candidate, that is, guarantees the stability of the dark matter. The dark matter candidate is proposed as the lightest mirror neutrino. This Z₂ discrete symmetry not only guarantees the stability of the dark matter but also controls the free parameters of the model such that they are significantly reduced. Then, mass spectrum of neutrinos is also discussed in two possible scenarios obtained by assigning charge under  Z₂ symmetry. For one of the scenarios we obtain the relic density for the dark matter candidate and the spin independent scattering cross section between dark matter and proton (neutron).

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• Flavourful axion and the Peccei-Quinn symmetry

  Stefan Daniel Nellen Mondragón

  020726 1-9

  Abstract:

  A model is presented, where the Froggatt-Nielsen and Peccei-Quinn symmetries are identified. This provides a solution to the strong CP problem and an explanation to the fermion mass hierarchy. At leading order, the quark mass matrix possess a Nearest-Neighbour-Interaction structure, while the neutrino mass matrix has a Majorana A2 texture. From a thorough numerical analysis the viability of this model is asserted, by comparing against current measurements. The data obtained from this analysis is then used to study properties from the axion.

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• The 3d O(4) model as an effective approach to the QCD phase diagram

  Edgar López-Contreras, José Antonio García-Hernández, Elías Natanael Polanco-Euán, Wolfgang Bietenholz

  020727 1-13

  Abstract:

  The QCD phase diagram is one of the most prominent outstanding puzzles within the Standard Model. Various experiments, which aim at its exploration beyond small baryon density, are operating or in preparation. From the theoretical side, this is an issue of non-perturbative QCD, and therefore of lattice simulations. However, a finite baryon density entails a technical problem (known as the “sign problem”), which has not been overcome so far. Here we present a study of an effective theory, the O(4) non-linear sigma model. It performs spontaneous symmetry breaking with the same Lie group structure as 2-flavor QCD in the chiral limit, which strongly suggests that they belong to the same universality class. Since we are interested in high temperature, we further assume dimensional reduction to the 3d O(4) model, which implies topological sectors. As pointed out by Skyrme, Wilczek and others, its topological charge takes the role of the baryon number. Hence the baryon chemical potential µB appears as an imaginary vacuum angle, which can be included in the lattice simulation without any sign problem. We present numerical results for the critical line in the chiral limit, and for the crossover in the presence of light quark masses. Their shapes are compatible with other predictions, but up to the value of about µB ≈ 300 MeV we do not find the notorious Critical Endpoint (CEP).

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• Transverse momentum dependent parton distribution functions and QCD evolution equations

  Martin Hentschinski

  020728 1-5

  Abstract:

  We provide an overview over Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs). While we will also comment on TMD PDFs in general, we will focus on their use for the description of hadronic reactions in the so-called low x limit. Here $x = M^2/s$ and $M$ is the hard scale of the process, while $\sqrt{s}$ is the center of mass energy of the reaction. We will explain why this are interesting quantities whose exploration serves a manifold purpose. In particular we will explain why these are interesting quantities both for the accurate description of LHC data and why exploration of such quantities is a central goal of the future Electron Ion Collider. In a second part of this talk we will then discuss how perturbative QCD allows us to formulate and solve differential equations, which describe the dependence of this TMD PDFs on various kinematic variables.

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• Graviton scattering amplitudes in first quantisation

  James Edwards

  020729 1-9

  Abstract:

  We give a pedagogical review to alternative, first quantised approaches to calculating graviton scattering amplitudes, giving an introduction to string inspired approaches and presenting more recent work based on the worldline formalism of quantum field theory that is motivated by these historic results. We describe how these first quantised techniques can greatly simplify the determination of such amplitudes, in particular reducing the number of Feynman-like diagrams that enter the computation and leading to compact results.

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