Shehu AbdusSalam, Chiara Crinò, Pramod Shukla
In the context of type IIB superstring compactifications on K3-fibred (weak) Swiss-cheese Calabi Yau (CY) orientifolds, we consider the realisation of de Sitter vacua obtained through the introduction of an anti-D3-brane at the tip of a highly warped throat of Klebanov-Strassler type. Aiming to have a concrete global realisation, we perform a systematic search for the CY threefolds with $2 < h^{1,1} < 5$ arising from the Kreuzer-Skarke database, which satisfy the minimal requirements of being K3-fibred and suitable for moduli stabilisation within the LARGE Volume Scenario (LVS). In this context, after scanning the set of K3-fibred CY threefolds with a so-called diagonal del-Pezzo divisor needed for LVS, we realise that one of the main challenging requirements for having anti-D3-brane uplifting is to find a suitable orientifold involution which can simultaneously result in a sufficient large $D3$ tadpole charge along with the presence of suitable $O3$-planes. In our detailed analysis (limited to) using the CY threefolds with small $h^{1,1}$, we observe that these topological requirements rule out most of the CY geometries leading to only few possibly suitable candidates for the purpose of anti-D3-brane uplifting. Subsequently, we present a global model using one such explicit K3-fibred CY threefold with $h^{1,1}=4$ in which all the moduli can be consistently stabilised in a de Sitter minimum of the scalar potential.
Shehu AbdusSalam, Maria Eugenia Cabrera
The observed Higgs boson signals to-date could be due to having two quasi-degenerate 125 GeV scalar states in Nature. This kind of scenario tallies well with the predictions from the Next-to-Minimal Supersymmetric Standard Model (NMSSM). We have analysed the phenomenological NMSSM Higgs boson couplings and derived a parameterization of the signal strengths within the two quasi-degenerate framework. With essentially two parameters, it is shown that the combined strengths of the two quasi-degenerate Higgs states in the leptonic (and b-quark) decay channels depart from the Standard Model values in the opposite direction to those in the vector boson channels. We identify experimental measurements for distinguishing a single from a double Higgs scenarios. The proposed parameterization can be used for benchmarking studies towards establishing the status of quasi-degenerate Higgs scenarios.
Shehu AbdusSalam, Leila Kalhor, Mohammad Mohammadidoust
We made global fits of the inert Higgs doublet model (IDM) in the light of collider and dark matter search limits and the requirement for a strongly first-order electroweak phase transition (EWPT). These show that there are still IDM parameter spaces compatible with the observational constraints considered. In particular, the data and theoretical requirements imposed favour the hypothesis for the existence of a scalar dark matter candidate around 100 GeV. This is mostly due to the pull towards lower masses by the EWPT constraint. The impact of electroweak precision measurements, the dark matter direct detection limits, and the condition for obtaining a strongly enough first-order EWPT, all have strong dependence, sometimes in opposing directions, on the mass splittings between the IDM scalars.
Gholamreza Fardipour Raki, Mohsen Khakzad, Shehu AbdusSalam
Photomultiplier tube (PMT) and Silicon Photo Multiplier (SiPM) are often used for detecting small number of photons or very weak radiations. A light guide usually connects these photodetectors to the test space. In this article, we investigate the effect of background signals caused by cosmic muons scintillation or interactions with PMT and SiPM, their light guide or input window materials. We study such interactions by making simulations using GATE software package and undertaking experiments using detector circuits developed as in~\cite{Raki:2022lwn}. The background cosmic muons can generate photons which will lead to errors in low radiation and single photon detection experiments especially if standard scintillators are not used. For such experiments, we conclude that the most useful method for cutting down the cosmic muons background should be by conducting the experiments deep underground or inside tunnels with several tens of meters of materials above it.
Shehu AbdusSalam, Layla Kalhor, Mohammad Javad Kazemi
For a cosmological first-order electroweak phase transition, requiring no sphaleron washout of baryon number violating processes leads to a lower bound on the strength of the transition. The velocity of the boundary between the phases, the so-called bubble wall, can become ultra-relativistic if the friction due to the plasma of particles is not sufficient to retard the wall's acceleration. This bubble ``runaway'' should not occur if a successful baryon asymmetry generation due to the transition is required. Using Boedeker-Moore criterion for bubble wall runaway, within the context of an extension of the standard model of particle physics with a real gauge-single scalar field, we show that a non runaway transition requirement puts an upper bound on the strength of the first-order phase transition.
Shehu AbdusSalam, Xin Gao, George K. Leontaris, Pramod Shukla
Given the huge size of the generic four-dimensional scalar potentials arising from the type II supergravities based on toroidal orientifolds, it is even hard to analytically solve the extremization conditions, and therefore the previous studies have been mainly focused on taking some numerical approaches. In this work, using the so-called {\it axionic flux polynomials} we demonstrate that the scalar potential and the extremization conditions can be simplified to a great extent, leading to the possibility of performing an analytic exploration of the flux landscape. In this regard, we consider the isotropic case of a type IIB model based on the standard ${\mathbb T}^6/({\mathbb Z}_2 \times {\mathbb Z}_2)$ orientifold having the three-form fluxes $F_3/H_3$ and the non-geometric $Q$-flux. This model results in around 300 terms in the scalar potential which depend on 6 moduli/axionic fields and 14 flux parameters. Considering that the axionic flux polynomials can take either zero or non-zero values results in the need of analyzing $2^{14}=16384$ candidate configurations, and we find that more than 16200 of those result in No-Go scenarios for Minkowskian/de-Sitter vacua. Based on our systematic exploration of non-tachyonic flux vacua, we present a detailed classification of such No-Go scenarios as well as the leftover ``undecided" configurations for which we could not conclude about the presence/absence of the stable Minkowskian/de-Sitter vacua.
Mohammad Javad Kazemi, Shehu AbdusSalam
We study the dynamics of electroweak phase transition in a simple extension of the Standard Model where the Higgs sector is extended by adding an $SU(2)_L$-triplet with hypercharge Y=2. By making random scans over the parameters of the model, we show that there are regions consistent with constraints from collider experiments and the requirement for a strong first-order electroweak phase transition which is needed for electroweak baryogenesis. Further, we also study the power spectrum of the gravitational waves which can be generated due to the first-order phase transitions. Moreover, the detectability of these gravitational waves, via future space-based detectors, is discussed.
Shehu AbdusSalam
There could be another scalar in nature quasi-degenerate with the observed one (h125). This is possible in models such as the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The scenario(s) with a single Higgs boson can be compared to that with multiple ones, all near 125 GeV. In order to assess the extent to which the current set of collider, cold dark matter relic density and direct detection limits are capable of discriminating these scenarios, we perform, for the first-time, global fits of a weak-scale phenomenological NMSSM with 26 free parameters using the nested sampling implementation in PolyChord, a next-generation tool for Bayesian inference. The analyses indicate that the data used shows a moderate tendency for supporting the scenario with an additional scalar much lighter than h125 with mass distribution centred below the W-boson mass. More stringent constraints are, however, needed for decisive inference regarding an additional Higgs boson with mass much less than or near 125 GeV.
Shehu AbdusSalam, Steven Abel, Deaglan Bartlett, Miguel Crispim Romão
We demonstrate the efficacy of symbolic regression (SR) to probe models of particle physics Beyond the Standard Model (BSM), by considering the so-called Constrained Minimal Supersymmetric Standard Model (CMSSM). Like many incarnations of BSM physics this model has a number (four) of arbitrary parameters, which determine the experimental signals, and cosmological observables such as the dark matter relic density. We show that analysis of the phenomenology can be greatly accelerated by using symbolic expressions derived for the observables in terms of the input parameters. Here we focus on the Higgs mass, the cold dark matter relic density, and the contribution to the anomalous magnetic moment of the muon. We find that SR can produce remarkably accurate expressions. Using them we make global fits to derive the posterior probability densities of the CMSSM input parameters which are in good agreement with those performed using conventional methods. Moreover, we demonstrate a major advantage of SR which is the ability to make fits using differentiable methods rather than sampling methods. We also compare the method with neural network (NN) regression. SR produces more globally robust results, while NNs require data that is focussed on the promising regions in order to be equally performant.
Shehu AbdusSalam, Safura Sadeghi Barzani, Mohammadreza Noormandipour
Experimental collaborations for the large hadron collider conducted many and various searches for supersymmetry. In the absence of signals, lower limits were put on sparticle masses but usually within frameworks with (over-) simplifications relative to the entire indications by supersymmetry models. For complementing current interpretations of experimental bounds, we introduce a 30-parameters version of the R-parity conserving minimal supersymmetric standard model (MSSM-30). Using a sample of the MSSM-30 which are in harmony with cold dark matter, flavour and precision electroweak constraints, we explicitly show the prospects for assessing neutralino candidate dark matter in contrast to future searches for supersymmetry. The MSSM-30 parameters regions that are beyond reach to dark matter direct detection experiments could be probed by future hadron-hadron colliders.
Shehu AbdusSalam, Christopher Hughes, Fernando Quevedo, Andreas Schachner
We present a comprehensive study of Kähler moduli stabilisation in Type IIB flux compactifications, combining advanced numerical techniques with analytical methods. Our JAX-based computational framework enables efficient scanning of the UV parameter space, while incorporating $α'$ corrections, loop and non-perturbative effects, as well as uplift contributions to the scalar potential. The implementation features rigorous vacuum validation protocols derived from analytic results. We apply our methods to explicit flux compactifications on more than 80,000 Calabi-Yau threefolds with $h^{1,1}\leq 6$ Kähler moduli. By systematically scanning over a wide range of values of the flux superpotential $W_0$ and the string coupling $g_s$, we find explicit realisations of every established Kähler moduli stabilisation scenario: for $10^{-15} \leq |W_0| \leq 10^{-2}$ we obtain both KKLT-like and Kähler uplifted vacua, while for the broader range $10^{-1} \leq |W_0| \leq 10^2$ we recover LVS as well as LVS-like hybrid solutions. Notably, we discover significant parameter regions where multiple vacua coexist within a single flux potential, including novel configurations pairing AdS, Minkowski, and dS minima with different volume hierarchies. These findings enable, for the first time, the analysis of vacuum decay processes within fixed flux configurations, complementing the established theory of transitions between distinct flux vacua and decays towards decompactification.
Shehu AbdusSalam, Steven Abel, Michele Cicoli, Fernando Quevedo, Pramod Shukla
Achieving full moduli stabilisation in type IIB string compactifications for generic Calabi-Yau threefolds with hundreds of Kähler moduli is notoriously hard. This is due not just to the very fast increase of the computational complexity with the number of moduli, but also to the fact that the scalar potential depends in general on the supergravity variables only implicitly. In fact, the supergravity chiral coordinates are 4-cycle volume moduli but the Kähler potential is an explicit function of the 2-cycle moduli and inverting between these two variables is in general impossible. In this paper we propose a general method to fix all type IIB Kähler moduli in a systematic way by working directly in terms of 2-cycle moduli: on one side we present a `master formula' for the scalar potential which can depend on an arbitrary number of Kähler moduli, while on the other we perform a computer-based search for critical points, introducing a hybrid Genetic/Clustering/Amoeba algorithm and other computational techniques. This allows us to reproduce several known minima, but also to discover new examples of both KKLT and LVS models, together with novel classes of LVS minima without diagonal del Pezzo divisors and hybrid vacua which share some features with KKLT and other with LVS solutions.
Shehu AbdusSalam, Steve Abel, Miguel Crispim Romao
We propose symbolic regression as a powerful tool for studying Beyond the Standard Model physics. As a benchmark model, we consider the so-called Constrained Minimal Supersymmetric Standard Model, which has a four-dimensional parameter space defined at the GUT scale. We provide a set of analytical expressions that reproduce three low-energy observables of interest in terms of the parameters of the theory: the Higgs mass, the contribution to the anomalous magnetic moment of the muon, and the cold dark matter relic density. To demonstrate the power of the approach, we employ the symbolic expressions in a global fits analysis to derive the posterior probability densities of the parameters, which are obtained extremely rapidly in comparison with conventional methods.
Jon Butterworth, Sabine Kraml, Harrison Prosper, Andy Buckley, Louie Corpe, Cristinel Diaconu, Mark Goodsell, Philippe Gras, Martin Habedank, Clemens Lange, Kati Lassila-Perini, André Lessa, Rakhi Mahbubani, Judita Mamužić, Zach Marshall, Thomas McCauley, Humberto Reyes-Gonzalez, Krzysztof Rolbiecki, Sezen Sekmen, Giordon Stark, Graeme Watt, Jonas Würzinger, Shehu AbdusSalam, Aytul Adiguzel, Amine Ahriche, Ben Allanach, Mohammad M. Altakach, Jack Y. Araz, Alexandre Arbey, Saiyad Ashanujjaman, Volker Austrup, Emanuele Bagnaschi, Sumit Banik, Csaba Balazs, Daniele Barducci, Philip Bechtle, Samuel Bein, Nicolas Berger, Tisa Biswas, Fawzi Boudjema, Jamie Boyd, Carsten Burgard, Jackson Burzynski, Jordan Byers, Giacomo Cacciapaglia, Cécile Caillol, Orhan Cakir, Christopher Chang, Gang Chen, Andrea Coccaro, Yara do Amaral Coutinho, Andreas Crivellin, Leo Constantin, Giovanna Cottin, Hridoy Debnath, Mehmet Demirci, Juhi Dutta, Joe Egan, Carlos Erice Cid, Farida Fassi, Matthew Feickert, Arnaud Ferrari, Pavel Fileviez Perez, Dillon S. Fitzgerald, Roberto Franceschini, Benjamin Fuks, Lorenz Gärtner, Kirtiman Ghosh, Andrea Giammanco, Alejandro Gomez Espinosa, Letícia M. Guedes, Giovanni Guerrieri, Christian Gütschow, Abdelhamid Haddad, Mahsana Haleem, Hassane Hamdaoui, Sven Heinemeyer, Lukas Heinrich, Ben Hodkinson, Gabriela Hoff, Cyril Hugonie, Sihyun Jeon, Adil Jueid, Deepak Kar, Anna Kaczmarska, Venus Keus, Michael Klasen, Kyoungchul Kong, Joachim Kopp, Michael Krämer, Manuel Kunkel, Bertrand Laforge, Theodota Lagouri, Eric Lancon, Peilian Li, Gabriela Lima Lichtenstein, Yang Liu, Steven Lowette, Jayita Lahiri, Siddharth Prasad Maharathy, Farvah Mahmoudi, Vasiliki A. Mitsou, Sanjoy Mandal, Michelangelo Mangano, Kentarou Mawatari, Peter Meinzinger, Manimala Mitra, Mojtaba Mohammadi Najafabadi, Sahana Narasimha, Siavash Neshatpour, Jacinto P. Neto, Mark Neubauer, Mohammad Nourbakhsh, Giacomo Ortona, Rojalin Padhan, Orlando Panella, Timothée Pascal, Brian Petersen, Werner Porod, Farinaldo S. Queiroz, Shakeel Ur Rahaman, Are Raklev, Hossein Rashidi, Patricia Rebello Teles, Federico Leo Redi, Jürgen Reuter, Tania Robens, Abhishek Roy, Subham Saha, Ahmetcan Sansar, Kadir Saygin, Nikita Schmal, Jeffrey Shahinian, Sukanya Sinha, Ricardo C. Silva, Tim Smith, Tibor Šimko, Andrzej Siodmok, Ana M. Teixeira, Tamara Vázquez Schröder, Carlos Vázquez Sierra, Yoxara Villamizar, Wolfgang Waltenberger, Peng Wang, Martin White, Kimiko Yamashita, Ekin Yoruk, Xuai Zhuang
Waleed Abdallah, Shehu AbdusSalam, Azar Ahmadov, Amine Ahriche, Gaël Alguero, Benjamin C. Allanach, Jack Y. Araz, Alexandre Arbey, Chiara Arina, Peter Athron, Emanuele Bagnaschi, Yang Bai, Michael J. Baker, Csaba Balazs, Daniele Barducci, Philip Bechtle, Aoife Bharucha, Andy Buckley, Jonathan Butterworth, Haiying Cai, Claudio Campagnari, Cari Cesarotti, Marcin Chrzaszcz, Andrea Coccaro, Eric Conte, Jonathan M. Cornell, Louie Dartmoor Corpe, Matthias Danninger, Luc Darmé, Aldo Deandrea, Nishita Desai, Barry Dillon, Caterina Doglioni, Juhi Dutta, John R. Ellis, Sebastian Ellis, Farida Fassi, Matthew Feickert, Nicolas Fernandez, Sylvain Fichet, Jernej F. Kamenik, Thomas Flacke, Benjamin Fuks, Achim Geiser, Marie-Hélène Genest, Akshay Ghalsasi, Tomas Gonzalo, Mark Goodsell, Stefania Gori, Philippe Gras, Admir Greljo, Diego Guadagnoli, Sven Heinemeyer, Lukas A. Heinrich, Jan Heisig, Deog Ki Hong, Tetiana Hryn'ova, Katri Huitu, Philip Ilten, Ahmed Ismail, Adil Jueid, Felix Kahlhoefer, Jan Kalinowski, Deepak Kar, Yevgeny Kats, Charanjit K. Khosa, Valeri Khoze, Tobias Klingl, Pyungwon Ko, Kyoungchul Kong, Wojciech Kotlarski, Michael Krämer, Sabine Kraml, Suchita Kulkarni, Anders Kvellestad, Clemens Lange, Kati Lassila-Perini, Seung J. Lee, Andre Lessa, Zhen Liu, Lara Lloret Iglesias, Jeanette M. Lorenz, Danika MacDonell, Farvah Mahmoudi, Judita Mamuzic, Andrea C. Marini, Pete Markowitz, Pablo Martinez Ruiz del Arbol, David Miller, Vasiliki Mitsou, Stefano Moretti, Marco Nardecchia, Siavash Neshatpour, Dao Thi Nhung, Per Osland, Patrick H. Owen, Orlando Panella, Alexander Pankov, Myeonghun Park, Werner Porod, Darren Price, Harrison Prosper, Are Raklev, Jürgen Reuter, Humberto Reyes-González, Thomas Rizzo, Tania Robens, Juan Rojo, Janusz A. Rosiek, Oleg Ruchayskiy, Veronica Sanz, Kai Schmidt-Hoberg, Pat Scott, Sezen Sekmen, Dipan Sengupta, Elizabeth Sexton-Kennedy, Hua-Sheng Shao, Seodong Shin, Luca Silvestrini, Ritesh Singh, Sukanya Sinha, Jory Sonneveld, Yotam Soreq, Giordon H. Stark, Tim Stefaniak, Jesse Thaler, Riccardo Torre, Emilio Torrente-Lujan, Gokhan Unel, Natascia Vignaroli, Wolfgang Waltenberger, Nicholas Wardle, Graeme Watt, Georg Weiglein, Martin J. White, Sophie L. Williamson, Jonas Wittbrodt, Lei Wu, Stefan Wunsch, Tevong You, Yang Zhang, José Zurita
Shehu S. AbdusSalam, Debajyoti Choudhury
The signal strength of the recently discovered Higgs boson-like particle in the diphoton channel seemingly constrains physics beyond the standard model to a severe degree. However, the reported signal strength is prone to possible underestimation of uncertainties. We propose a discriminant that is relatively free of many of the theoretical uncertainties, and use this to gauge the impact on the phenomenological MSSM. A Bayesian global fit to all the pre-LHC data results in posterior distributions for the masses that are neither very restrictive, nor sufficiently prior-independent (except for the Higgs and stop masses). The imposition of the Higgs data, on the other hand, yields interesting and nearly prior-independent constraints. In particular, the existence of some light superpartners is favoured.
Joseph P. Conlon, Shehu S. Abdussalam, Fernando Quevedo, Kerim Suruliz
This paper develops the computation of soft supersymmetry breaking terms for chiral D7 matter fields in IIB Calabi-Yau flux compactifications with stabilised moduli. We determine explicit expressions for soft terms for the single-modulus KKLT scenario and the multiple-moduli large volume scenario. In particular we use the chiral matter metrics for Calabi-Yau backgrounds recently computed in hep-th/0609180. These differ from the better understood metrics for non-chiral matter and therefore give a different structure of soft terms. The soft terms take a simple form depending explicitly on the modular weights of the corresponding matter fields. For the large-volume case we find that in the simplest D7 brane configuration, scalar masses, gaugino masses and A-terms are very similar to the dilaton-dominated scenario. Although all soft masses are suppressed by ln(M_P/m_{3/2}) compared to the gravitino mass, the anomaly-mediated contributions do not compete, being doubly suppressed and thus subdominant to the gravity-mediated tree-level terms. Soft terms are flavour-universal to leading order in an expansion in inverse Kahler moduli. They also do not introduce extra CP violating phases to the effective action. We argue that soft term flavour universality should be a property of the large-volume compactifications, and more generally IIB flux models, in which flavour is determined by the complex structure moduli while supersymmetry is broken by the Kahler moduli. For the simplest large-volume case we run the soft terms to low energies and present some sample spectra and a basic phenomenological analysis.
Shehu S. AbdusSalam, Joseph P. Conlon, Fernando Quevedo, Kerim Suruliz
We scan the landscape of flux compactifications for the Calabi-Yau manifold $\mathbb{P}^4_{[1,1,1,6,9]}$ with two K\" ahler moduli by varying the value of the flux superpotential $W_0$ over a large range of values. We do not include uplift terms. We find a rich phase structure of AdS and dS vacua. Starting with $W_0\sim 1$ we reproduce the exponentially large volume scenario, but as $W_0$ is reduced new classes of minima appear. One of them corresponds to the supersymmetric KKLT vacuum while the other is a new, deeper non-supersymmetric minimum. We study how the bare cosmological constant and the soft supersymmetry breaking parameters for matter on D7 branes depend on $W_0$, for these classes of minima. We discuss potential applications of our results.
Shehu S. AbdusSalam
The ATLAS collaboration published supersymmetry limits based on up to about 4.7 \ifb data collected over the year 2011 from LHC runs at 7 TeV. These were mainly interpreted within restricted, particular or simplified models for supersymmetry breaking schemes or scenarios. The pMSSM is an alternative and more generic supersymmetry framework which captures broader phenomenological features. Searching for more generic conclusions from the supersymmetry limits interpretation, we update a Bayesian global fit of the pMSSM to pre-LHC data using the LHC-7 limits. The posterior distributions show the most up to date features, revealing allowed versus excluded regions in sparticle mass planes within the MSSM.
Shehu S. AbdusSalam
Up until now a complete scan in all phenomenologically relevant directions of the MSSM at the TeV scale for performing global fit has not been done. Given the imminent start of operation of the LHC, this is a major gap on our quest to discovering and understanding the physical implications of low energy supersymmetry. The main reason for this is the large number of parameters involved that makes it computationally extremely expensive using the traditional methods. In this talk I demonstrate that with advanced sampling techniques the problem is solvable. The results from the explored 24-parameter TeV scale MSSM (phenoMSSM) are remarkably distinct from previous studies and are independent of models for supersymmetry breaking and mediation mechanisms. Hence they are a more robust guide to searches for supersymmetry and dark matter.