diff --git "a/9dFPT4oBgHgl3EQfYjT_/content/tmp_files/load_file.txt" "b/9dFPT4oBgHgl3EQfYjT_/content/tmp_files/load_file.txt" new file mode 100644--- /dev/null +++ "b/9dFPT4oBgHgl3EQfYjT_/content/tmp_files/load_file.txt" @@ -0,0 +1,1812 @@ +filepath=/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf,len=1811 +page_content='Prepared for submission to JHEP Dynamic Radius Jet Clustering Algorithm Biswarup Mukhopadhyayaa, Tousik Samuia, and Ritesh K.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Singha aDepartment of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' E-mail: biswarup@iiserkol.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='ac.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='in, tousiksamui@gmail.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='com, ritesh.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='singh@iiserkol.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='ac.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='in Abstract: The study of standard QCD jets produced along with fat jets, which may appear as a result of the decay of a heavy particle, has become an essential part of collider studies.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Current jet clustering algorithms, which use a fixed radius parameter for the formation of jets from the hadrons of an event, may be inadequate to capture the differing radius features.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In this work, we develop an alternative jet clustering algorithm that allows the radius to vary dynamically based on local kinematics and distribution in the η-φ plane inside each evolving jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We present the usefulness of this dynamic radius clustering algorithm through two Standard Model processes, and thereafter illustrate it for a scenario beyond the Standard Model at the 13 TeV LHC.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' arXiv:2301.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='13074v1 [hep-ph] 30 Jan 2023 Contents 1 Introduction 1 2 Methodology 3 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='1 Standard Sequential Recombination Algorithms 3 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='2 Our Proposal: Dynamic Radius Jet Clustering Algorithm 4 3 Application to Standard Model Processes 7 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='1 Illustration I: pp → tj process 8 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='2 Illustration II: pp → V j Subprocess 15 4 Usefulness in BSM signals 19 5 Summary and Outlook 25 1 Introduction The physics extraction capacity of any high-energy collider depends crucially on the han- dling of coloured particles in various final states.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These are produced as partons via ei- ther short-distance interactions of quantum chromodynamics (QCD) or electroweak pro- cesses [1, 2].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The partons, however, hadronize through long-distance QCD effects which are not calculable ab initio.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' One rather uses semi-empirical methods to predict the prob- ability that energetic partons will fragment into more low-energy partons and ultimately form colour-neutral hadrons which are observable in the detector.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Groups of closely spaced hadrons with varied degrees of collimation form ‘jets’ whose identification, isolation, and merger are predicted once more with the help of semi-empirical (and by no means uniquely decided) algorithms called jet clustering algorithms [3–7].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The aim always remains to define jets with such algorithms which most accurately elicit the short-distance physics underly- ing the events that are studied.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' They thus constitute some of our most important tools in the analysis of phenomena at colliders.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In the context of the Large Hadron Collider (LHC), a widely used class of jet criteria is based on so-called kt-type sequential recombination jet algorithms [7–13].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These algorithms (briefly discussed in the next section) typically try to merge ‘neighbouring’ hadrons to identify the group as a jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The neighbourhood of a hadron is defined by a single radius parameter R0 in the η-φ plane of the detector, which is used to quantify the radius (or size) of a jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' This is because the hadrons within R0 are merged to form a jet while the hadrons outside R0 are not included in that jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The choices for the value of R0 in these algorithms depend on the physics searches one is carrying out.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' At the 13 TeV LHC, the typical choices for R0 are 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='4 or 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='8 for a ‘narrow’ or a ‘fat’ jet, respectively.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' There are, in addition, jet isolation criteria depending on whether one is trying to separate a jet from a hard lepton or another hadronic jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' However, the sequential recombination algorithms generally do not accommodate varying choices of radii on a jet-by-jet basis in a single event since they – 1 – have a single constant parameter that determines the radius of a jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Separate classifiers for a ‘narrow’ jet and a ‘fat’ jet in a single event in the current kt-type algorithms are thus difficult to set.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' An important improvement over the current fixed radius algorithms would be to make them adapt the jet radii dynamically jet-by-jet in each event.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We make an attempt in this direction in this work.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Our central idea of choosing the radius dynamically of a jet, especially for a boosted fat jet, is based on the kinematics of the decay products of the initiating heavy particle.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' From the theoretical side, the formation of boosted fat jet occurs due to the high collimation of the on-shell decay products – and their showering and subsequent hadronization – of the energetic and therefore boosted heavy particles.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' This is very different from the formation of light quark- or gluon-initiated jets, whose collimation is primarily due to parton showering and subsequent hadronization.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' On the other hand, at the operational level, as per the standard kt-type algorithms, the fat jets are formed in the same way as the regular ‘narrow’ jets, which are initiated by light quarks or gluons.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' However, the kinematics of on-shell decay products and their radiation pattern of a heavy particle is different from the showering of energetic light quarks or gluons.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Therefore, the internal structure of a fat jet is very different from a narrow one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These internal structure has been used to tag different heavy and light jets in the LHC context.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' For example, jet substructure (JSS) observable generalized angularities λκ β [14, 15] is used to distinguish between quark- and gluon-initiated jets [16– 26].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The same variable was used in the classification among the narrow jet, fat W jet, or boosted top jet [27–30].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Another important set of JSS observables, namely the energy correlation functions (ECFs) [31, 32], was shown to be useful in classifying different types of jets [29, 33–37].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The observable N-subjettiness (τN) [38, 39] has been used to find the multi-pronged nature of light or heavy jets [40–65].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These variables have also been used extensively by the experimental collaborations at the 13 TeV LHC [66–68].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These examples try to exploit the energy distribution pattern inside a jet to distinguish a heavy object from a QCD jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The common theme of these jet substructure variables is the utilization of the ‘multi-pronged’ nature of the fat jets.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Due to this multi-pronged nature, one expects the variance of inter-constituent distance ∆R of a fat jet to be significantly different compared to the narrow QCD jets.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' This variance of a jet can be used to grow the radius of a jet starting from an initial radius.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Earlier attempts to make the jet radius variable, albeit with somewhat different motivations and formalisms, can be found in references [69, 70].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In Ref.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' [69], the effective radius of a pseudojet during their evolution was taken to be inversely proportional to the pT with a maximum cut-off on the radius.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Essentially, this algorithm starts from a big effective radius and the size shrinks as a process of evolution.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' On the other hand, in Ref.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' [70], an expectation-maximization approach was taken for clustering the hadrons into a pre-determined number of clusters (jets).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Our approach, in this work, is to modify the standard fixed radius kt-type algorithms to make the radius grow depending on the local kinematics and distribution (in the η-φ plane) of the hadrons.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The rest of the article is organized as follows.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In section 2, we briefly outline the kt-type sequential recombination algorithms followed by our improvement to the same.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We test the efficacy of our algorithms on two SM processes and discuss them in section 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Section 4 deals with one application in the BSM scenario.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We summarize and conclude in section 5.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' – 2 – 2 Methodology 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='1 Standard Sequential Recombination Algorithms At the operational level, a jet is constituted by a bunch of four-momenta obtained using some clustering algorithm.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Among various possible ways of grouping up the four-momenta of an event, we need to choose those relevant to physics at the collider.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' It is important that the clustering algorithm should ensure infrared and collinear (IRC) safety, which, in our context, can be defined in terms of the following conditions [7]: Infrared (IR) safety: The output of the algorithm should not be affected by the intro- duction of a four-momentum with p → 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Collinear (C) safety: The output of the algorithm should not be affected by a collinear splitting of any four-momentum.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The algorithm that best takes care of the issue of IRC safety is known as kt-type sequential recombination jet clustering algorithms [7].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We briefly outline these algorithms below1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' If an event consists of N final state particles, whose four-momenta are taken in a list as an input of the kt-type algorithms.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The distance dij between the ith and jth four-momenta and the distance diB between the ith and the beam are then defined as dij = min � p2p Ti, p2p Tj � ∆R2 ij, (2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='1) diB = p2p TiR2 0, (2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='2) where R0 is the radius parameter of the algorithm, ∆Rij is the Euclidean distance between the ith and jth four-momenta in the η-φ plane, and pTi is pT of ith four-momenta.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The exponent p sets the weight factor to the Euclidean distance in the η-φ plane.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The three choices of p = 1, 0 and −1 correspond to the kt (KT) [8–10], Cambridge-Aachen (CA) [11, 12], and anti-kt (AK) [13] algorithms, respectively.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The algorithm for combining nearby four-momenta with respect to the above distance measures to form jets has the following steps.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Step 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The distances dij for all the possible pairs and beam distances diB for all the four-momenta are calculated first.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Step 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The minimum among all the dij and diB’s is determined.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Step 3a.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' If the minimum occurs at one of the i, j pairs, the corresponding ith and jth four-momenta are merged to form a new four-momentum.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The older ones, ith and jth four-momenta are removed from the list and the newly merged one is added to the list and goes back to Step 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Step 3b.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' On the other hand, if the minimum distance is one of the diB, the ith four- momenta is declared as a final jet, and it is removed from the list and goes back to Step 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' 1Here, we only discuss the inclusive algorithms in the LHC context.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' For other jet clustering algorithms, please see Ref.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' [7].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' – 3 – Step 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The process is stopped once the list gets empty.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' This class of algorithms is seedless because the clustering of four-momenta to form a jet does not start from a particular seed.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Rather, the algorithms try to merge the closest pair first.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' A group of hadrons is then declared as a jet when an appropriate size is reached.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The essential difference among the three different algorithms, viz.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' AK, CA, and KT is that they give different weights to the Euclidean distance in the η-φ plane.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' This typically sets some sort of seed to the clustering algorithms in the sense that it gives a preference to a hadron around which four-momenta merge to give rise to a final jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In the case of the KT algorithm, it is the softer (in terms of pT ) constituent which merges first and then the harder ones get attached to it.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' As a result, the shape of the final jet may not be circular in the η-φ plane.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' On the other hand, in the AK algorithm, the hardest particle in a neighbourhood becomes some sort of seed for the jet and the softer ones merge at a later stage.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Hence the final jet looks circular in the η-φ plane.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In the CA algorithm, the merging is purely angular.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Among the three algorithms, the AK algorithm is the most popular one owing to its circular shape.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Importantly, in the kt-type algorithms, there is a fixed radius parameter R0, whose value dictates the typical size of all the jets in a particular event.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We note that these algorithms are unable to capture the essential features of the events where narrow and fat jets may simultaneously arise.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In our proposed algorithm, we have modified these algorithms to bring out the features of varying sizes of the jets.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='2 Our Proposal: Dynamic Radius Jet Clustering Algorithm The usual kt-type algorithms take a fixed radius as an input parameter, and hence the algorithms return all the jets to be of the same size (or narrower) in a single event.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' This lack of dynamicity in choosing a radius can be overcome by setting the radius parameter dynamically during the construction of each jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' In any kt-type algorithm, the starting point is a list of N four-momenta of particles.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We will refer to these as fundamental particles or, sometimes, fundamental four-momenta.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The algorithm follows Steps 1 to 3b, as defined in section 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='1, iteratively until the list gets empty.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' At every iteration, the number of contents of the list gets reduced by one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' The reduction happens in two ways: (1) via the merger of two four-momenta, (2) via the declaration of four-momentum as a final jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Thus at an intermediate iteration, the list contains two different types of objects.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These two types of objects are (1) fundamental four-momenta, and (2) composite four-momenta, generated through the merger of two or more fundamental four-momenta.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' These composite objects evolve through iterations to give rise to the final jets.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' For our convenience, let us label these composite evolving objects as pseudojets.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' We borrowed the name pseudojet from the PseudoJet class in the FastJet3 package [71], where all the types of four-momenta are called pseudojet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' However, we will call them by different names: fundamental, pseudojet (composite or evolving), and jet (or final jet).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Our proposal is to change the constant nature of the radius parameter R0 in Eq.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' (2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='2) to a dynamic quantity depending on the distribution, in the η-φ plane, of the fundamental objects inside each evolving pseudojet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' Therefore, the modified distance measure for the – 4 – dynamic radius algorithm takes the form dij = min � p2p Ti, p2p Tj � ∆R2 ij, (2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='3) diB = p2p Ti R2 di, (2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='4) where Rdi is the dynamical radius parameter, defined as Rdi = R0 + σi.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' (2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content='5) The constant R0 is an input parameter similar to the standard kt-type algorithm and it is the starting point of the dynamical growth of the radius of an evolving jet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/9dFPT4oBgHgl3EQfYjT_/content/2301.13074v1.pdf'} +page_content=' For the ith pseudojet, σi is calculated as σ2 i = � a