Vector Boson Fusion A powerful tool to discover new physics at the LHC Andr´esFl´orez July 31, 2018 Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 1 / LHC31 Generalities of the Standard Model (SM) Fundamental particles and their 2 † † 2 V (φ) = −µ φ (φ) + λ(φ φ) (2) interactions: Abelian higgs potential SU(3)C ⊗ SU(2)L ⊗ U(1)Y, (1) ) φ u c t γ V( d s b g H Im( φ e µ τ Z Boson de Higgs ) φ Re( ) W νe νµ ντ 2 2 2 ν 2 µ Quarks Leptones Bosones |h0|φ|0i| = , with ν = − (3) 2 λ Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 2 / LHC31 The Large Hadron Collider (LHC) Figure: Sketch of the LHC. The main Figure: Sketch of the acceleration chain at the experiments are: CMS, ATLAS, ALICE and LHC LHCb Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 3 / LHC31 The Large Hadron Collider (LHC) Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 4 / LHC31 Figure: Sketch of the acceleration chain at the LHC The Large Hadron Collider (LHC) Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 5 / LHC31 Figure: Sketch of the acceleration chain at the LHC The CMS Detector Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 6 / LHC31 Detection of Particles Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 7 / LHC31 The CMS Detector Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 8 / LHC31 3 Coordinate systems 4 Pseudorapidity 5 η-gaps. 6 Missing transverse momentum p/T Some important concepts In particle physics, a cross section (σ) 1 Cross Section represents the probability of production of 2 Luminosity a specific process. This quantity is related with the level of the interaction between the beam and the target, or between two beams, and it depends on the energy of collisions. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 9 / LHC31 4 Pseudorapidity 5 η-gaps. 6 Missing transverse momentum p/T Some important concepts 1 Cross Section 2 Luminosity N × N × f × F L ∼ A B (4) 3 Coordinate systems 4π(σA × σB ) Z L = Ldt (5) Ni = σi × L (6) Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 9 / LHC31 5 η-gaps. 6 Missing transverse momentum p/T Some important concepts Y Detector 1 Cross Section Punto de Z Dirección Colision del haz θ ϕ 2 Luminosity 3 Coordinate systems 4 Pseudorapidity X Centro del LHC Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 9 / LHC31 6 Missing transverse momentum p/T Some important concepts h θ i η ≡ − ln tan . 2 1 Cross Section 2 Luminosity 3 Coordinate systems 4 Pseudorapidity 5 η-gaps. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 9 / LHC31 Some important concepts h θ i η ≡ − ln tan . 2 1 Cross Section 2 Luminosity 3 Coordinate systems 4 Pseudorapidity 5 η-gaps. 6 Missing transverse momentum p/T Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 9 / LHC31 Some important concepts X T ~pi = 0, i 1 Cross Section X X = ~pT (visible) + ~pT (invisible) 2 Luminosity j k j k 3 Coordinate systems X X ~pT (invisible) = − ~pT (visible) 4 Pseudorapidity k j k j 5 η-gaps. 6 Missing transverse momentum p/T X T p/T = − ~pj (visible) (4) j Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at the 9 / LHC31 The algorithm uses the information from the different sub-detectors to reconstruct individual particle candidates: Muons, electrons, photons, charged and neutral hadrons. The reconstructed particles are then used to reconstruct more complicated objets such as jets (see next) and hadronic taus (τh), and to also to measure the p/T in the event. Particle Flow Algorithm - CMS The Particle Flow (PF) algorithm used by the CMS collaboration, has no precedent in the history of HEP. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 10 the / LHC31 The reconstructed particles are then used to reconstruct more complicated objets such as jets (see next) and hadronic taus (τh), and to also to measure the p/T in the event. Particle Flow Algorithm - CMS The Particle Flow (PF) algorithm used by the CMS collaboration, has no precedent in the history of HEP. The algorithm uses the information from the different sub-detectors to reconstruct individual particle candidates: Muons, electrons, photons, charged and neutral hadrons. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 10 the / LHC31 Particle Flow Algorithm - CMS The Particle Flow (PF) algorithm used by the CMS collaboration, has no precedent in the history of HEP. The algorithm uses the information from the different sub-detectors to reconstruct individual particle candidates: Muons, electrons, photons, charged and neutral hadrons. The reconstructed particles are then used to reconstruct more complicated objets such as jets (see next) and hadronic taus (τh), and to also to measure the p/T in the event. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 10 the / LHC31 Particle Flow Algorithm - CMS The Particle Flow (PF) algorithm used by the CMS collaboration, has no precedent in the history of HEP. The algorithm uses the information from the different sub-detectors to reconstruct individual particle candidates: Muons, electrons, photons, charged and neutral hadrons. The reconstructed particles are then used to reconstruct more complicated objets such as jets (see next) and hadronic taus (τh), and to also to measure the p/T in the event. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 10 the / LHC31 Particle Flow Algorithm - CMS The Particle Flow (PF) algorithm used by the CMS collaboration, has no precedent in the history of HEP. The algorithm uses the information from the different sub-detectors to reconstruct individual particle candidates: Muons, electrons, photons, charged and neutral hadrons. The reconstructed particles are then used to reconstruct more complicated objets such as jets (see next) and hadronic taus (τh), and to also to measure the p/T in the event. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 10 the / LHC31 2 Jet reconstruction Some important concepts 1 Jet 1 Partonic 2 Hadronic 3 Detector Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 11 the / LHC31 Some important concepts 1 Jet 1 Partonic 2 Hadronic 3 Detector 2 Jet reconstruction Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 11 the / LHC31 Some important concepts π − + Jet 1 − π Κ + Κ + π π 0 1 Jet 1 Partonic 2 Hadronic 3 Detector π − Vertice primario 2 Jet reconstruction π + Κ + π − π 0 Jet 2 Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 11 the / LHC31 Jet Reconstruction Algorithms The identification of jets in collider experiments is very important. Cone-based reconstruction algorithms are of common use in particle physics. Determining the boundary of a cone for a reconstructed jet it is not a trivial problem, due to the repetitive branching nature of QCD radiation. There are two main classes of jet-reconstruction algorithms: 1 The iterative cone. 2 The sequential clustering, which includes the Kt and Anti−Kt algorithms. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 12 the / LHC31 Important considerations There are to important aspects that any jet algorithm must consider: The jet size and if the algorithm is infra-red and collinear(IRC) safe. The area of the cone enclosing the jet determine how much soft radiation is allowed. When a large jet radius is set, it allows to include enough particles from the hadronization process. Therefore, there is a good accuracy when the jet mass and energy are estimated. Nevertheless, with large jet radius, the jet mass and energy can often be overestimated due to Underlying Event (UE) and Pile-Up (PU) effects. The UE and PU effect can be reduced with a smaller jet radius. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 13 the / LHC31 Reconstruction of Hadronic Tau Leptons Taus (τ) are the heaviest known leptons: Mass 1.777 GeV. Because of their large mass, taus can decay both leptonically and hadronically. The table shows the decay branching fraction for taus. Note that hadronic final states are the dominant decay modes : 64.8%. Andr´esFl´orez Vector Boson Fusion A powerful tool to discoverJuly new 31, physics 2018 at 14 the / LHC31 Electroweak SUSY Searches Searches in the color sector have not yield positive signs of SUSY until now. SUSY searches in the electroweak (EWK) sector open a different avenue to find new physics: X Smaller predicted cross sections but lower levels of hadronic activity.