SearcharxivSearch

arXiv subjects

Sonny Mantry

Publications and source records attributed to Sonny Mantry.

At least 19 recordsLinked to original sources

Hadronization effects and electroweak contributions in DIS one-jettiness

We study the structure of leading hadronization effects and the contributions of massive electroweak gauge boson exchange in the $τ_1$ and $τ_{1a}$ 1-Jettiness global event shapes for deep inelastic scattering (DIS). The leading hadronization effects in $τ_1$ acquire a non-trivial dependence on the hard scattering kinematics. This kinematic dependence is explicitly calculable, so that the leading hadronization effects in $τ_1$, $τ_{1a}$, and DIS thrust are universal and described by the same underlying shape function. The additional calculable kinematic dependence in $τ_1$ provides an independent lever arm for simultaneously constraining hadronization effects in these observables. We present corresponding results at the N$^3$LL+${\cal O}(α_s^2)$ level of accuracy. We extend previous results by including the contributions mediated by the exchange of the massive $Z$ and $W$ electroweak gauge bosons for neutral current (NC) and charged current (CC) DIS, respectively, including ${\cal O}(α_s)$ QCD corrections to obtain N$^2$LL+${\cal O}(α_s)$ results. We compare theoretical predictions to Pythia simulation and demonstrate the universality of leading hadronization effects across NC and CC DIS processes and a wide range of kinematics relevant to HERA and the EIC.

hep-ph

Universality and Kinematic Dependence of Hadronization Effects in DIS Global Event Shapes

We propose a unified framework for a combined global analysis to constrain leading hadronization effects across the 1-Jettiness class of global event shapes for Deep Inelastic Scattering (DIS). We show that for the subclass of jet-based event shapes where the leading jet direction is determined dynamically event-by-event, the leading hadronization effects can acquire a non-trivial dependence on the hard scattering kinematics. However, this dependence is explicitly calculable, allowing for universality of leading hadronization effects in the 1-Jettiness class. The non-trivial kinematic dependence provides an independent lever arm for simultaneously constraining hadronization effects in the jet-based and DIS thrust event shapes. This universality, combined with the kinematic lever arm, could allow for including the typically ignored peak region, where hadronization effects are most severe, in precision extractions of the strong coupling. We demonstrate the need for such a unified treatment of hadronization effects through comparisons of theoretical predictions with simulation data.

hep-ph

Impact of QED Radiation on SMEFT Constraints in Deep Inelastic Scattering

Deep-inelastic scattering (DIS) provides a powerful probe of physics beyond the Standard Model through precision measurements interpreted within the Standard Model Effective Field Theory (SMEFT). We study the impact of collision-induced QED radiation on SMEFT constraints using the joint QCD+QED factorization framework based on lepton distribution and fragmentation functions. QED radiation can substantially modify DIS cross sections and, in some kinematic regions, significantly alter the effective momentum transfer relevant for factorization. We find that while cross sections receive order-one corrections, longitudinal electron spin asymmetries are affected only at the few-percent level, making them significantly more robust observables for SMEFT studies. Benchmark projections for SoLID and the Electron-Ion Collider are provided to demonstrate the impact of QED radiation for future precision DIS analyses and the extraction of SMEFT constraints.

hep-ph

Jet Charge with Global Event Shapes: Probing Quark Flavor Dynamics

We propose measuring the jet electric charge of jet regions, defined within the framework of global event shapes, as a probe of quark flavor dynamics within the nucleon and the hadronization process. In particular, we consider a measurement of the jet region charge while simultaneously keeping track of the energy flow throughout the event, as characterized by the global event shape. As a concrete example, we focus on the measurement of the 1-Jettiness jet charge ($Q$), the jet charge of the jet region ($J$) defined within the framework of the 1-Jettiness global event shape ($τ_1$) for the Deep Inelastic Scattering (DIS) process, $e^- + p \to e^- + J + X$, with unpolarized or longitudinally polarized protons. The 1-Jettiness distribution, binned according to jet charge, allows for enhanced quark flavor separation of the initial state unpolarized or polarized PDFs. On the other hand, the jet charge distribution binned by 1-Jettiness can serve as a probe of quark flavor dynamics in the final state hadronization process. We derive a factorization theorem for simultaneous measurements of $τ_1$ and $Q$ in the resummation region, $τ_1 \ll P_{J_T}$, where $P_{J_T}$ denotes the transverse momentum of the jet region. The factorization theorem contains a new universal charged jet function, generalizing the standard jet function to include a jet charge measurement. Therefore these universal functions can be extracted from a global analysis of N-jettiness and thrust at $e^+e^-$ colliders. We provide simulation studies to demonstrate the sensitivity of the 1-Jettiness jet charge observable to quark flavor dynamics in nucleon structure and explore the possibility of probing the final state hadronization process. This observable is well-suited for applications with existing HERA data and the future Electron-Ion Collider (EIC).

hep-ph

Weak Charge Form Factor Determination at the Electron-Ion Collider

Determining the weak charge form factor, $F_W(Q^2)$, of nuclei over a continuous range of momentum transfers, $0\lesssim Q^2 \lesssim 0.1$ GeV$^2$, is essential for mapping out the distribution of neutrons in nuclei. The neutron density distribution has significant implications for a broad range of areas, including studies of nuclear structure, neutron stars, and physics beyond the Standard Model. Currently, our knowledge of $F_W(Q^2)$ comes primarily from fixed target experiments that measure the parity-violating asymmetry in coherent elastic electron-ion scattering. Fixed target experiments, such as CREX and PREX-1,2, have provided high-precision weak charge form factor extractions for the $^{48}{\rm Ca}$ and $^{208}{\rm Pb}$ nuclei, respectively. However, a major limitation of fixed target experiments is that they each provide data only at a single value of $Q^2$. With the proposed Electron-Ion Collider (EIC) on the horizon, we explore its potential to impact the determination of the weak charge form factor. While it cannot compete with the precision of fixed target experiments, it can provide data over a wide and continuous range of $Q^2$ values, and for a wide variety of nuclei. We show that with data corresponding to an integrated luminosity of ${\cal L} \sim $ 500/$A$ fb$^{-1}$, where $A$ is the nucleus atomic weight, the EIC can significantly impact constraints by lifting degeneracies in theoretical models of the neutron density distribution. Ensuring EIC detector coverage at low $Q^2$ and large negative pseudorapidities will be essential for such $F_W(Q^2)$ measurements.

hep-ph

Nonperturbative Corrections to Soft Drop Jet Mass

We provide a quantum field theory based description of the nonperturbative effects from hadronization for soft drop groomed jet mass distributions using the soft-collinear effective theory and the coherent branching formalism. There are two distinct regions of jet mass $m_J$ where grooming modifies hadronization effects. In a region with intermediate $m_J$ an operator expansion can be used, and the leading power corrections are given by three universal nonperturbative parameters that are independent of all kinematic variables and grooming parameters, and only depend on whether the parton initiating the jet is a quark or gluon. The leading power corrections in this region cannot be described by a standard normalized shape function. These power corrections depend on the kinematics of the subjet that stops soft drop through short distance coefficients, which encode a perturbatively calculable dependence on the jet transverse momentum, jet rapidity, and on the soft drop grooming parameters $z_{\rm cut}$ and $β$. Determining this dependence requires a resummation of large logarithms, which we carry out at LL order. For smaller $m_J$ there is a nonperturbative region described by a one-dimensional shape function that is unusual because it is not normalized to unity, and has a non-trivial dependence on $β$.

hep-ph

The DIS 1-Jettiness Event Shape at N$^3$LL+${\cal O}(α_s^2)$

We present results for the $τ_1$ and $τ_{1a}$ 1-Jettiness global event shape distributions, for Deep Inelastic Scattering (DIS), at the N$^3$LL + ${\cal O}(α_s^2)$ level of accuracy. These event-shape distributions quantify and characterize the pattern of final state radiation in electron-nucleus collisions. They can be used as a probe of nuclear structure functions, nuclear medium effects in jet production, and for a precision extraction of the QCD strong coupling. The results presented here, along with the corresponding numerical codes, can be used for analyses with HERA data, in EIC simulation studies, and for eventual comparison with real EIC data.

hep-ph

Complete Formalism of Cross Sections and Asymmetries for Longitudinally and Transversely Polarized Leptons and Hadrons in Deep Inelastic Scattering

Studies of the Deep Inelastic Scattering (DIS) have provided fundamental information of the nucleon structure for decades. The electron-ion collider (EIC) will be the first collider capable of DIS study with both polarized lepton and polarized hadron beams, providing the possibility of accessing new electroweak structure functions of the nucleon. In this work, we completed the DIS cross section derivations for both longitudinally and transversely polarized leptons and hadrons, with no approximations made, and with all three contributions $γγ, γZ, ZZ$ included. These results were derived using primarily tensor algebra and Feynman calculus, starting from previously established leptonic and hadronic tensors and carry out their contraction. Our results are presented in terms of both spin-averaged and spin-dependent cross sections, allowing direct comparison with experimentally measured cross sections and their asymmetries. We include also in our discussion comparisons of different conventions that exist in the literature.

hep-ph

Report of the Topical Group on Top quark physics and heavy flavor production for Snowmass 2021

This report summarizes the work of the Energy Frontier Topical Group on EW Physics: Heavy flavor and top quark physics (EF03) of the 2021 Community Summer Study (Snowmass). It aims to highlight the physics potential of top-quark studies and heavy-flavor production processes (bottom and charm) at the HL-LHC and possible future hadron and lepton colliders and running scenarios.

hep-ph

Neutral-Current Electroweak Physics and SMEFT Studies at the EIC

We study the potential for precision electroweak (EW) measurements and beyond-the-Standard Model (BSM) searches using cross-section asymmetries in neutral-current (NC) deep inelastic scattering at the electron-ion collider (EIC). Our analysis uses a complete and realistic accounting of systematic errors from both theory and experiment and considers the potential of both proton and deuteron beams for a wide range of energies and luminosities. We also consider what can be learned from a possible future positron beam and a potential ten-fold luminosity upgrade of the EIC beyond its initial decade of running. We use the SM effective field theory (SMEFT) framework to parameterize BSM effects and focus on semi-leptonic four-fermion operators, whereas for our precision EW study, we determine how well the EIC can measure the weak mixing angle. New features of our study include the use of an up-to-date detector design of EIC Comprehensive Chromodynamics Experiment (ECCE) and accurate running conditions of the EIC, the simultaneous fitting of beam polarization uncertainties and Wilson coefficients to improve the sensitivity to SMEFT operators, and the inclusion of the weak mixing angle running in our fit template. We find that the EIC can probe BSM operators at scales competitive with and in many cases exceeding LHC Drell-Yan bounds while simultaneously not suffering from degeneracies between Wilson coefficients.

hep-ph

Probing charged lepton flavor violation with a positron beam at CEBAF (JLAB)

The addition of a high intensity 11 GeV polarized positron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) at JLAB would allow for a search of Charged Lepton Flavor Violation (CLFV) via the process $e^+N \rightarrow μ^+ X$. The proposed Solenoidal Large Intensity Detector (SoLID) spectrometer, in the configuration with muon chambers, would be ideal for such CLFV searches. Various new physics scenarios, including the phenomenologically convenient Leptoquark (LQ) framework, predict CLFV rates that are within reach of current or planned experiments. A positron beam with instantaneous luminosity, ${\cal L}\sim 10^{38}$ cm$^{-2}$s$^{-1}$, could improve on existing HERA limits by two or three orders of magnitude. The availability of positron beam polarization would also allow for distentangling CLFV effects mediated by left-handed vs. right-handed LQs.

hep-ph

Dynamic Jet Charge

We propose a modified definition of the jet charge, the "dynamic jet charge", where the constant jet momentum fraction weighting parameter, $κ$, in the standard jet charge definition is generalized to be a function of a dynamical property of the jet or the individual jet constituents. The dynamic jet charge can complement analyses based on the standard definition and give improved discrimination between quark and gluon initiated jets and between jets initiated by different quark flavors. We focus on the specific scenario where each hadron in the jet contributes to the dynamic jet charge with a $κ$-value dynamically determined by its jet momentum fraction. The corresponding dynamic jet charge distributions have qualitatively distinct features and are typically characterized by a multiple peak structure. For proton-proton collisions, compared to the standard jet charge, the dynamic jet charge gives significantly improved discrimination between quark and gluon initiated jets and comparable discrimination between $u$- and $d$-quark initiated jets. In Pythia simulations of heavy ion collisions, the dynamic jet charge is found to have higher jet discrimination power compared to the standard jet charge, remaining robust against the increased contamination from underlying event. We also present phenomenological applications of the dynamic jet charge to probe nuclear flavor structure.

hep-ph

Jet Charge: A Flavor Prism for Spin Asymmetries at the EIC

We propose the jet charge observable as a novel probe of flavor structure in the nucleon spin program at the Electron Ion Collider (EIC). We show that jet charge measurements can substantially enhance the sensitivity of spin asymmetries to different partonic flavors in the nucleon. This sensitivity can be further improved by constructing the jet charge using only a subset of hadron species (pions or kaons) in the jet. As an example, we use the Sivers asymmetry in back-to-back electron-jet production at the EIC to show that the jet charge can be a unique tool in constraining the Sivers function for different partonic flavors.

hep-ph

Extracting a Short Distance Top Mass with Light Grooming

We propose a kinematic method based on a factorization formula for precisely measuring the top quark mass $m_t$ in $pp$ collisions using boosted top jets with light soft drop grooming. By using light grooming, which is an order of magnitude less aggressive than typical grooming, we retain a universal description of the top mass scheme and decay effects, while still effectively removing soft contamination from the top jet. We give field theory results for the hadronization corrections for jets induced by a heavy top quark, showing they are described by a universal hadronic parameter that also appears for groomed light quark jets. An important phenomenological application of our results is that one can obtain $m_t$ in a short distance scheme by fitting the hadron level jet mass distributions, predicted by our factorization formula, to data or by Monte-Carlo calibration. The peaked distributions for $pp$ and $e^+e^-$ collisions are similar, up to sensitivity to underlying event which is significantly reduced by soft drop. Since soft drop implies that the $t$ and $\bar t$ jet masses each can be independently measured, the analysis enables the use of lepton+jet samples.

hep-ph

The 1-Jettiness DIS Spectrum: Factorization, Resummation, and Jet Algorithm Dependence

The 1-Jettiness (tau_1) event shape for Deep Inelastic Scattering (DIS), allows for a quantitative and global description of the pattern of QCD radiation for single jet (J) production in electron-nucleus (N_A) collisions e^- + N_A \to e^- + J + X. It allows for precision studies of QCD and is a sensitive probe of nuclear structure and dynamics. The large transverse momentum (P_{J_T}) of the final state jet $J$, characterizes the hard scale in the problem. The region of phase space where tau_1 << P_{J_T}, corresponds to configurations where energetic radiation (E~ P_{J_T}) is only along either the single jet direction or the beam direction with only soft radiation (E ~ τ_1 <<P_{J_T}) in between. Thus, the restriction tau_1 << P_{J_T} corresponds to a veto on additional jets and leads to large Sudakov logarithms of τ_1/P_{J_T} that must be resummed. Based on a factorization framework, derived using the Soft Collinear Effective Theory (SCET), we provide resummation results at the NNLL level of accuracy and match them onto the NLO result in fixed order perturbation theory, appropriate in the τ_1 \sim P_{J_T} region where additional jets and hard radiation are allowed. The τ_1-distribution depends on the jet algorithm used to find the leading jet in the region tau_1 ~ P_{J_T}, unlike the resummation region where this dependence is power suppressed in tau_1/P_{J_T} << 1. We give results for the entire tau_1 spectrum, with a smooth matching between the resummation region and fixed-order region, where we make use of the anti-kt jet algorithm. The 1-Jettiness event shape can be a powerful probe of nuclear and QCD dynamics at future electron-ion colliders and by analyzing existing HERA data.

hep-ph

Differences between Axions and Generic Light Scalars in Laboratory Experiments

It is well-known that electric dipole moment (EDM) constraints provide the most stringent bounds on axion-mediated macroscopic spin-dependent (SD) and time reversal and parity violating (TVPV) forces. These bounds are several orders of magnitude stronger than those arising from direct searches in fifth-force experiments and combining astrophysical bounds on stellar energy loss with Eotvos tests of the weak equivalence principle (WEP). This is a consequence of the specific properties of the axion, invoked to solve the Strong CP problem. However, the situation is quite different for generic light scalars that are unrelated to the strong CP problem. In this case, bounds from fifth-force experiments and astrophysical processes are far more stringent than the EDM bounds, for the mass range explored in direct searches.

hep-ph

Distinguishing axions from generic light scalars using EDM and fifth-force experiments

We derive electric dipole moment (EDM) constraints on possible new macroscopic time reversal and parity violating (TVPV) spin-dependent forces. These constraints are compared to those derived from direct searches in fifth-force experiments and from combining laboratory searches with astrophysical bounds on stellar energy loss. For axion-mediated TVPV spin-dependent forces, EDM constraints dominate over fifth-force limits by several orders of magnitude. However, we show that for a generic light scalar, unrelated to the strong CP problem, present bounds from direct fifth- force searches are more stringent than those inferred from EDM limits, for the interaction ranges explored by fifth-force experiments. Thus, correlating observations in EDM and fifth-force experiments could help distinguish axions from more generic light scalar scenarios.

hep-ph

Probing nuclear dynamics in jet production with a global event shape

We study single jet production in electron-nucleus collisions e^- + N_A -> J + X, using the 1-jettiness (τ_1) global event shape. It inclusively quantifies the pattern of radiation in the final state, gives enhanced sensitivity to soft radiation at wide angles from the nuclear beam and final-state jet, and facilitates the resummation of large Sudakov logarithms associated with the veto on additional jets. Through their effect on the observed pattern of radiation, 1-jettiness can be a useful probe of nuclear PDFs and power corrections from dynamical effects in the nuclear medium. This formalism allows for the standard jet shape analysis while simultaneously providing sensitivity to soft radiation at wide angles from the jet. We use a factorization framework for cross-sections differential in $τ_1$ and the transverse momentum (P_{J_T}) and rapidity (y) of the jet, in the region τ_1<< P_{J_T}. The restriction $τ_1 << P_{J_T}$ allows only soft radiation between the nuclear beam and jet directions, thereby acting as a veto on additional jets. This region is also insensitive to the details of the jet algorithm, allowing for better theoretical control over resummation, while providing enhanced sensitivity to nuclear medium effects. We give numerical results at leading twist, with resummation at the next-to-next-to-leading logarithmic (NNLL) level of accuracy, for a variety of nuclear targets. Such studies would be ideal for the EIC and the LHeC proposals for a future electron-ion collider, where a range of nuclear targets are planned.

hep-ph