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  • 1.
    Aydemir, Ufuk
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Interpretation of the 750 GeV diphoton excess with colored scalars in SO(10) grand unification2016Artikel i tidskrift (Refereegranskat)
  • 2.
    Aydemir, Ufuk
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    LHC Probes of TeV-Scale Scalars in SO(10) Grand Unification2017Ingår i: Advances in High Energy Physics, ISSN 1687-7357, E-ISSN 1687-7365, artikel-id 7498795Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the possibility of TeV-scale scalars as low energy remnants arising in the nonsupersymmetric SO(10) grandunification framework where the field content is minimal.We consider a scenario where the SO(10) gauge symmetry is broken intothe gauge symmetry of the Standard Model (SM) through multiple stages of symmetry breaking, and a colored and hyperchargedscalar 𝜒 picks a TeV-scale mass in the process. The last stage of the symmetry breaking occurs at the TeV-scale where the leftrightsymmetry, that is, SU(2)𝐿 ⊗ SU(2)𝑅 ⊗ U(1)𝐵−𝐿 ⊗ SU(3)𝐶, is broken into that of the SM by a singlet scalar field S of mass𝑀S ∼ 1TeV, which is a component of an SU(2)𝑅-triplet scalar field, acquiring a TeV-scale vacuum expectation value. For the LHCphenomenology, we consider a scenario where S is produced via gluon-gluon fusion through loop interactions with 𝜒 and alsodecays to a pair of SM gauge bosons through 𝜒 in the loop.We find that the parameter space is heavily constrained from the latestLHC data.We use a multivariate analysis to estimate the LHC discovery reach of S into the diphoton channel.

  • 3.
    Aydemir, Ufuk
    et al.
    Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China;Huazhong Univ Sci & Technol, Sch Phys, Wuhan 430074, Hubei, Peoples R China.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Univ Delhi, Dept Phys & Astrophys, Delhi 110007, India.
    Mitra, Subhadip
    Int Inst Informat Technol, Ctr Computat Nat Sci & Bioinformat, Hyderabad 500032, Telangana, India.
    Addressing the R-D(*) anomalies with an S-1 leptoquark from SO(10) grand unification2020Ingår i: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 101, nr 1, artikel-id 015011Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Motivated by the R-D(*) anomalies, we investigate an SO(10) grand unification scenario where a charge -1/3 scalar leptoquark (S-1) remains as the only new physics candidate at the TeV scale. This leptoquark along with the Standard Model (SM) Higgs doublet originates from the same ten-dimensional real scalar multiplet in the SO(10) grand unification framework taking its mass close to the electroweak scale. We explicitly show how the gauge coupling unification is achieved with only one intermediate symmetrybreaking scale at which the Pati-Salam gauge group is broken into the SM group. We investigate the phenomenological implications of our scenario and show that an S-1 with a specific Yukawa texture can explain the R-D(*) anomalies. We perform a multiparameter scan considering the relevant flavor constraints on R-D(*), F-L(D*), P-tau(D*) and R-K(*)(vv) as well as the constraint coming from the Z -> tau tau decay and the latest Dr resonance search data at the LHC. Our analysis shows that a single leptoquark solution to the observed R-D(*) anomalies with S-1 is still a viable solution.

  • 4. Benbrik, Rachid
    et al.
    Bergeås Kuutmann, Elin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Franzosi, Diogo Buarque
    Ellajosyula, Venugopal
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ferretti, Gabriele
    Isacson, Max
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Liu, Yao-Bei
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mathisen, Thomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Moretti, Stefano
    Panizzi, Luca
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Signatures of vector-like top partners decaying into new neutral scalar or pseudoscalar bosons2019Ingår i: Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    We explore the phenomenology of models containing one Vector-Like Quark (VLQ), t′, which can decay into the Standard Model (SM) top quark, t, and a new spin-0 neutral boson, S, the latter being either a scalar or pseudoscalar state. We parametrise the underlying interactions in terms of a simplified model which enables us to capture possible Beyond the SM (BSM) scenarios. We discuss in particular three such scenarios: one where the SM state is supplemented by an additional scalar, one which builds upon a 2-Higgs Doublet Model (2HDM) framework and another which realises a Composite Higgs Model (CHM) through partial compositeness. Such exotic decays of the t′ can be competitive with decays into SM particles, leading to new possible discovery channels at the Large Hadron Collider (LHC). Assuming t′ pair production via strong interactions, we design signal regions optimised for one t′→St transition (while being inclusive on the other \bar{t'} decay, and vice versa), followed by the decay of S into the two very clean experimental signatures S→γγ and S→Z(→ℓ+ℓ−)γ. We perform a dedicated signal-to-background analysis in both channels, by using Monte Carlo (MC) event simulations modelling the dynamics from the proton-proton to the detector level. Under the assumption of BR(t′→St)=100%, we are therefore able to realistically quantify the sensitivity of the LHC to both the t′ and S masses, assuming both current and foreseen luminosities. This approach paves the way for the LHC experiments to surpass current VLQ search strategies based solely on t′ decays into SM bosons (W±,Z, h).

  • 5.
    Bhardwaj, Akanksha
    et al.
    PRL, Ahmadabad 380009, Gujarat, India;Indian Inst Technol, Gandhinagar 382424, Gujarat, India.
    Konar, Partha
    PRL, Ahmadabad 380009, Gujarat, India.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Sadhukhan, Soumya
    Univ Delhi, Dept Phys & Astrophys, Delhi 110007, India.
    Probing the inert doublet model using jet substructure with a multivariate analysis2019Ingår i: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 100, nr 5, artikel-id 055040Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We explore the challenging but phenomenologically interesting hierarchical mass spectrum of the inert doublet model where relatively light dark matter along with much heavier scalar states can fully satisfy the constraints on the relic abundance and also fulfill other theoretical as well as collider and astrophysical bounds. To probe this region of parameter space at the LHC, we propose a signal process that combines up to two large radius boosted jets along with substantial missing transverse momentum. Aided by our intuitive signal selection, we capture a hybrid process where the di-fatjet signal is significantly enhanced by the mono-fatjet contribution with minimal effects on the SM di-fatjet background. Substantiated by the sizable mass difference between the scalars, these boosted jets, originally produced from the hadronic decay of massive vector bosons, still carry the inherent footprint of their root. These features implanted inside the jet substructure can provide additional handles to deal with a large background involving QCD jets. We adopt a multivariate analysis using a boosted decision tree to provide a robust mechanism to explore the hierarchical scenario, which would bring almost the entire available parameter space well within reach of the 14 TeV LHC runs with high luminosity.

  • 6.
    Camargo-Molina, Jose Eliel
    et al.
    Lund Univ, Dept Astron & Theoret Phys, SE-22362 Lund, Sweden..
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Univ Delhi, Dept Phys & Astrophys, Delhi 110007, India..
    Pasechnik, Roman
    Lund Univ, Dept Astron & Theoret Phys, SE-22362 Lund, Sweden..
    Wessen, Jonas
    Lund Univ, Dept Astron & Theoret Phys, SE-22362 Lund, Sweden..
    Heavy charged scalars from cs̄ fusion: a generic search strategy applied to a 3HDM with U(1) x U(1) family symmetry2018Ingår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 3, artikel-id 024Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We describe a class of three Higgs doublet models (3HDMs) with a softly broken U(1) x U(1) family symmetry that enforces a Cabibbo-like quark mixing while forbidding tree-level flavour changing neutral currents. The hierarchy in the observed quark masses is partly explained by a softer hierarchy in the vacuum expectation values of the three Higgs doublets. As a consequence, the physical scalar spectrum contains a Standard Model (SM) like Higgs boson h(125) while exotic scalars couple the strongest to the second quark family, leading to rather unconventional discovery channels that could be probed at the Large Hadron Collider. In particular, we describe a search strategy for the lightest charged Higgs boson H-+/-, through the process c -> H+ -> W+ h(125), using a multivariate analysis that leads to an excellent discriminatory power against the SM background. Although the analysis is applied to the proposed class of 3HDMs, we employ a model-independent formulation such that it can be applied to any other model with the same discovery channel.

  • 7.
    Chandak, Kushagra
    et al.
    Int Inst Informat Technol, Ctr Computat Nat Sci & Bioinformat, Hyderabad 500032, India.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mitra, Subhadip
    Int Inst Informat Technol, Ctr Computat Nat Sci & Bioinformat, Hyderabad 500032, India.
    Hunting for scalar leptoquarks with boosted tops and light leptons2019Ingår i: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 100, nr 7, artikel-id 075019Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The LHC search strategies for leptoquarks that couple dominantly to a top quark are different than for the ones that couple mostly to the light quarks. We consider charge 1/3 (phi(1)) and 5/3 (phi(5)) scalar leptoquarks that can decay to a top quark and a charged lepton (tl) giving rise to a resonance system of a boosted top and a high-p(T) lepton. We introduce simple phenomenological models suitable for bottom-up studies and explicitly map them to all possible scalar leptoquark models within the Buchmuller-Ruckl-Wyler classifications that can have the desired decays. We study pair and single productions of these leptoquarks. Contrary to the common perception, we find that the single production of top-philic leptoquarks phi = {phi(1), phi(5)} in association with a lepton and jets could be significant for order one phi tl coupling in certain scenarios. We propose a strategy of selecting events with at least one hadronic-top and two high-p(T) same flavor opposite sign leptons. This captures events from both pair and single productions. Our strategy can significantly enhance the LHC discovery potential especially in the high-mass region where single productions become more prominent. Our estimation shows that a scalar leptoquark as heavy as similar to 1.7 TeV can be discovered at the 14 TeV LHC with 3 ab(-1) of integrated luminosity in the tll + X channel for 100% branching ratio in the phi -> tl decay mode. However, in some scenarios, the discovery reach can increase beyond 2 TeV even though the branching ratio comes down to about 50%.

  • 8.
    Danielsson, Ulf
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Teoretisk fysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Heavy photophilic scalar at the LHC from a varying electromagnetic coupling2017Ingår i: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 919, s. 569-582Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the phenomenology of a heavy scalar ϕ of the type involved in Bekenstein's framework for varying electromagnetic coupling theories, with the difference that the scalar in our model has a large mass. The model has only two free parameters, the mass Mϕ of the scalar and the scale Λ of new physics. The scalar is dominantly produced through photon-photon fusion at the LHC and leads to a diphoton final state. It can also be produced by quark-antiquark fusion in association with a photon or a fermion pair. Its dominating decay is to diphotons, but it also has a large three-body branching to a fermion pair and a photon, which can provide an interesting search channel with a dilepton-photon resonance. We derive exclusion limits on the Mϕ−Λplane from the latest 13 TeV LHC diphoton resonance search data. For a benchmark mass of Mϕ∼1 TeV, we find a lower limit on Λ of 18 TeV. We discuss the more complex possibility of varying couplings in the full electroweak theory and comment on the possibility that the new physics is related to extra dimensions or string theory.

  • 9.
    Danielsson, Ulf
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Teoretisk fysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Swedish Collegium for Advanced Study, Thunbergsvägen 2, SE-752 38 Uppsala, Sweden.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Varying gauge couplings and collider phenomenology2019Ingår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 100, nr 5, artikel-id 055028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we investigate a natural extension of the Standard Model that involves varying coupling constants. This is a general expectation in any fundamental theory such as string theory, and there are good reasons for why new physics could appear at reachable energy scales. We investigate the collider phenomenology of models with varying gauge couplings where the variations are associated with real singlet scalar fields. We introduce three different heavy scalar fields that are responsible for the variations of the three gauge couplings of the Standard Model. This gives rise to many interesting collider signatures that we explore, resulting in exclusion limits based on the most recent LHC data, and predictions of the future discovery potential at the high-luminosity LHC.

  • 10.
    Ekstedt, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Löfgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Constraining minimal anomaly free U(1) extensions of the Standard Model2016Ingår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 1611, artikel-id 071Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We consider a class of minimal anomaly free U(1) extensions of the Standard Model with three generations of right-handed neutrinos and a complex scalar. Using electroweak precision constraints, new 13 TeV LHC data, and considering theoretical limitations such as perturbativity, we show that it is possible to constrain a wide class of models. By classifying these models with a single parameter, κ, we can put a model independent upper bound on the new U(1) gauge coupling gz. We find that the new dilepton data puts strong bounds on the parameters, especially in the mass region MZ′≲3 TeV.

  • 11.
    Ekstedt, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Löfgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Department of Physics and AstrophysicsUniversity of DelhiDelhiIndia.
    Minimal anomalous U(1) theories and collider phenomenology2018Ingår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 1802, s. 152-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study the collider phenomenology of a neutral gauge boson Z′ arising in minimal but anomalous U(1) extensions of the Standard Model (SM). To retain gauge invariance of physical observables, we consider cancellation of gauge anomalies through the Green-Schwarz mechanism. We categorize a wide class of U(1) extensions in terms of the new U(1) charges of the left-handed quarks and leptons and the Higgs doublet. We derive constraints on some benchmark models using electroweak precision constraints and the latest 13 TeV LHC dilepton and dijet resonance search data. We calculate the decay rates of the exotic and rare one-loop Z′ decays to ZZ and Z-photon modes, which are the unique signatures of our framework. If observed, these decays could hint at anomaly cancellation through the Green-Schwarz mechanism. We also discuss the possible observation of such signatures at the LHC and at future ILC colliders.

  • 12.
    Kumar, Mukesh
    et al.
    Univ Witwatersrand, Natl Inst Theoret Phys, Johannesburg.
    von Buddenbrock, Stefan
    Univ Witwatersrand, South Africa..
    Chakrabarty, Nabarun
    Harish Chandra Res Inst, India..
    Cornell, Alan S.
    Univ Witwatersrand, Natl Inst Theoret Phys, South Africa.; Univ Witwatersrand, South Africa..
    Kar, Deepak
    Univ Witwatersrand, South Africa..
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mellado, Bruce
    Univ Witwatersrand, South Africa..
    Mukhopadhyaya, Biswarup
    Harish Chandra Res Inst, India..
    Reed, Robert G.
    Univ Witwatersrand, South Africa..
    The impact of additional scalar bosons at the LHC2017Ingår i: HIGH ENERGY PARTICLE PHYSICS WORKSHOP 2016, IOP PUBLISHING LTD , 2017, artikel-id UNSP 012007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this study we consider an effective model by introducing two hypothetical real scalars, H and chi - a dark matter candidate, where the masses of these scalars are 2m(h) < m(H) < 2m(t) and m(chi) approximate to m(h)/2 with m(h) and m(t) being the Standard Model Higgs boson and top quark masses, respectively. A distortion in the transverse momentum distributions of h in the intermediate region of the spectrum through the processes pp -> H -> h(chi chi) could be observed in this model. An additional scalar, S, has been postulated to explain large H -> h(chi chi) branching ratios, assuming m(h) less than or similar to m(s) less than or similar to mH - m(h) and m(s) > 2m(chi). Furthermore, a scenario of a two Higgs doublet model (2HDM) is introduced and a detailed proposal at the present energies of the Large Hadron Collider to study the extra CP-even (h, H), CP-odd (A) and charged (H-+/-) scalars has been pursued. With possible phenomenological implications, production and decay modes for these scalars are discussed. Based on the mass spectrum of H, A and H-+/-, the production of multi-leptons and Z+jets+missing-energy events are predicted. A specific, Type-II 2HDM model is discussed in detail.

  • 13.
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Exclusion Limits on a Scalar Decaying to Photons and Distinguishing Its Production Mechanisms2018Ingår i: Advances in High Energy Physics, ISSN 1687-7357, E-ISSN 1687-7365, artikel-id 9150617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    LHCrun-II has a great potential to search for new resonances in the diphoton channel. Latest 13 TeV data already put stringent limits on the cross sections in the diphoton channel assuming the resonance is produced through the gluon-gluon fusion. Many beyond the Standard Model (SM) theories predict TeV-scale scalars, which copiously decay to diphotons. Apart from the gluon-gluon fusion production, these scalars can also be dominantly produced in other ways too at the LHC, namely, through the quark-quark fusion or the gauge boson fusions like the photon-photon, photon-Z, WW, or ZZ fusions. In this paper we use an effective field theory approach where a heavy scalar can be produced in various ways and recast the latest ATLAS diphoton resonance search to put model-independent limits on its mass and effective couplings to the SM particles. If a new scalar is discovered at the LHC, it would be very important to identify its production mechanism in order to probe the nature of the underlying theory. We show that combining various kinematic variables in a multivariate analysis can be very powerful to distinguish different production mechanisms from one another.

  • 14.
    Mandal, Tanumoy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Danielsson, Ulf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Teoretisk fysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    The 750 GeV excess from photon-photon and quark-quark processes2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The observed excess in the diphoton mass spectrum around 750 GeV at the 13 TeV LHC possibly indicates the presence of a photonphilic resonance. We show that the excess can be explained by a scalar of the type involved in Bekenstein's framework for varying electromagnetic coupling theories. The scalar, in our model, couples dominantly to photons and is mainly produced by the quark-quark fusion at the LHC. In addition, it can also be produced in photon-photon fusion. Our model has only two free parameters, the mass of the scalar and the scale of the new physics, which are fixed by the LHC excess to 750 GeV and 1.5 - 2 TeV, respectively. The scalar has a large three-body decay to a fermion pair and a photon, which provides an interesting search channel with a dilepton-photon resonance around 750 GeV.

  • 15.
    Mandal, Tanumoy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ekstedt, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Enberg, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Löfgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Exclusion Limits on Minimal Anomaly Free U(1) Extensions of the Standard Model2018Ingår i: XXII DAE HIGH ENERGY PHYSICS SYMPOSIUM / [ed] Naimuddin, M, SPRINGER-VERLAG BERLIN , 2018, s. 243-246Konferensbidrag (Refereegranskat)
  • 16.
    Mandal, Tanumoy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Jaikumar, Prashanth
    Calif State Univ Long Beach, Dept Phys & Astron, Long Beach, CA 90840 USA..
    Effect of Strong Magnetic Field on Competing Order Parameters in Two-Flavor Dense Quark Matter2017Ingår i: Advances in High Energy Physics, ISSN 1687-7357, E-ISSN 1687-7365, artikel-id 6472909Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study the effect of strong magnetic field on competing chiral and diquark order parameters in a regime of moderately dense quarkmatter. Theinterdependence of the chiral and diquark condensates through nonperturbative quark mass and strong coupling effects is analyzed in a two-flavorNambu-Jona-Lasinio (NJL) model. In the weak magnetic field limit, our results agree qualitatively with earlier zero-field studies in the literature that find a critical coupling ratio G(D/)G(S) similar to 1.1 below which chiral or superconducting order parameters appear almost exclusively. Above the ratio, there exists a significant mixed broken phase region where both gaps are nonzero. However, a strongmagnetic field greater than or similar to 10(18)G disrupts this mixed broken phase region and changes a smooth crossover found in the weak-field case to a first-order transition for both gaps at almost the same critical density. Our results suggest that in the two-flavor approximation to moderately dense quark matter strong magnetic field enhances the possibility of a mixed phase at high density, with implications for the structure, energetics, and vibrational spectrum of neutron stars.

  • 17.
    Mandal, Tanumoy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Univ Delhi, Dept Phys & Astrophys, Delhi 110007, India.
    Mitra, Subhadip
    Int Inst Informat Technol, Ctr Computat Nat Sci & Bioinformat, Hyderabad 500032, India.
    Raz, Swapnil
    Int Inst Informat Technol, Ctr Computat Nat Sci & Bioinformat, Hyderabad 500032, India.
    R-D(*) motivated S-1 leptoquark scenarios: Impact of interference on the exclusion limits from LHC data2019Ingår i: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 99, nr 5, artikel-id 055028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Motivated by the persistent anomalies in the semileptonic B-meson decays, we investigate the competency of LHC data to constrain the R-D(*)-favored parameter space in a charge -1/3 scalar leptoquark (S-1) model. We consider some scenarios with one large free coupling to accommodate the R-D(*) anomalies. As a result, some of them dominantly yield nonresonant tau tau and tau nu events at the LHC through the t-channel S-1 exchange. So far, no experiment has searched for leptoquarks using these signatures and the relevant resonant leptoquark searches are yet to put any strong exclusion limit on the parameter space. We recast the latest tau tau and tau nu resonance search data to obtain new exclusion limits. The nonresonant processes strongly interfere (destructively in our case) with the Standard Model background and play the determining role in setting the exclusion limits. To obtain precise limits, we include non-negligible effects coming from the subdominant (resonant) pair and inclusive single leptoquark productions systematically in our analysis. To deal with large destructive interference, we make use of the transverse mass distributions from the experiments in our statistical analysis. In addition, we also recast the relevant direct search results to obtain the most stringent collider bounds on these scenarios to date. These are independent bounds and are competitive to other known bounds. Finally, we indicate how one can adopt these bounds to a wide class of models with S-1 that are proposed to accommodate the R-D(*) anomalies.

  • 18.
    Mandal, Tanumoy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Harish Chandra Res Inst, Reg Ctr Accelerator Based Particle Phys, Chhatnag Rd, Allahabad 211019, Uttar Pradesh, India..
    Mitra, Subhadip
    Int Inst Informat Technol, Ctr Computat Nat Sci & Bioinformat, Hyderabad 500032, Andhra Pradesh, India..
    Seth, Satyajit
    Johannes Gutenberg Univ Mainz, Inst Phys, PRISMA Cluster Excellence, D-55099 Mainz, Germany..
    Pair production of scalar leptoquarks at the LHC to NLO parton shower accuracy2016Ingår i: PHYSICAL REVIEW D, ISSN 2470-0010, Vol. 93, nr 3, artikel-id 035018Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the scalar leptoquark pair production process at the LHC computed at the next-to-leading order in QCD, matched to the PYTHIA parton shower using the MC@NLO formalism. We consider the leading order decay of a leptoquark to a lepton (e, mu, tau or nu(e), nu(mu), nu(tau)) and a jet and observe the effects of parton shower on the final states. For demonstration, we display the kinametical distributions of a selection of observables along with their scale uncertainties for the 13 TeV LHC. We also present pair production cross sections and K-factors using a massless five-quark flavor scheme for different LHC center-of-mass energies. The complete stand-alone code is available online.

  • 19.
    Mandal, Tanumoy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mitra, Subhadip
    Seth, Satyajit
    Probing Compositeness with the CMS eejj & eej Data2016Ingår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 758, s. 219-225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Quark-lepton compositeness is a well-known beyond the Standard Model (SM) scenario with heavy exotic particles like leptoquarks (LQs) and leptogluons (LGs) etc. These particles can couple to leptons and jets simultaneously. In this letter, we use the recent CMS scalar LQ search data in the eejj and eej channels to probe this scenario. We recast the data in terms of a color octet partner of the SM electron (or a first generation spin-1/2 LG) that couples to an electron and a gluon via a dimension five operator suppressed by the quark-lepton compositeness scale (Lambda). By combining different production processes of the color octet electron (e(8)) at the LHC, we use the CMS 8 TeV data to obtain a simultaneous bound on Lambda and the mass of the e(8) (M-e8). We also study the reach of the 13 TeV LHC to discover the e(8) and interpret the required luminosity in terms of M-e8 and Lambda.

  • 20.
    von Buddenbrock, Stefan
    et al.
    Univ Witwatersrand, Sch Phys, ZA-2050 Johannesburg, South Africa..
    Chakrabarty, Nabarun
    Harish Chandra Res Inst, Reg Ctr Accelerator Based Particle Phys, Chhatnag Rd, Allahabad 211019, Uttar Pradesh, India..
    Cornell, Alan S.
    Univ Witwatersrand, Natl Inst Theoret Phys, Sch Phys, ZA-2050 Johannesburg, South Africa.;Univ Witwatersrand, Mandelstam Inst Theoret Phys, ZA-2050 Johannesburg, South Africa..
    Kar, Deepak
    Univ Witwatersrand, Sch Phys, ZA-2050 Johannesburg, South Africa..
    Kumar, Mukesh
    Univ Witwatersrand, Natl Inst Theoret Phys, Sch Phys, ZA-2050 Johannesburg, South Africa.;Univ Witwatersrand, Mandelstam Inst Theoret Phys, ZA-2050 Johannesburg, South Africa..
    Mandal, Tanumoy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Mellado, Bruce
    Univ Witwatersrand, Sch Phys, ZA-2050 Johannesburg, South Africa..
    Mukhopadhyaya, Biswarup
    Harish Chandra Res Inst, Reg Ctr Accelerator Based Particle Phys, Chhatnag Rd, Allahabad 211019, Uttar Pradesh, India..
    Reed, Robert G.
    Univ Witwatersrand, Sch Phys, ZA-2050 Johannesburg, South Africa..
    Ruan, Xifeng
    Univ Witwatersrand, Sch Phys, ZA-2050 Johannesburg, South Africa..
    Phenomenological signatures of additional scalar bosons at the LHC2016Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 76, nr 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the search prospects for new scalars beyond the standard model at the large hadron collider (LHC). In these studies two real scalars S and x have been introduced in a two Higgs-doublet model (2HDM), where S is a portal to darkmatter (DM) through its interaction with., a DM candidate and a possible source of missing transverse energy (E-T(miss)). Previous studies focussed on a heavy scalar H decay mode H. h.., which was studied using an effective theory in order to explain a distortion in the Higgs boson (h) transverse momentum spectrum (von Buddenbrock et al. in arXiv:1506.00612[hep-ph], 2015). In this work, the effective decay is understood more deeply by including a mediator S, and the focus is changed to H -> hS, SS with S -> xx. Phenomenological signatures of all the new scalars in the proposed 2HDM are discussed in the energy regime of the LHC, and theirmass bounds have been set accordingly. Additionally, we have performed several analyses with final states including leptons and Emiss T, with H -> 4W, t (t) H -> 6W and A -> ZH channels, in order to understand the impact these scalars have on current searches.

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